Automated vehicle for use in inventory management system

ABSTRACT

A vehicle for use in an inventory management system having a plurality of destination areas and a guide system includes a platform for receiving and transporting items to and from the destination areas, a plurality of motors, a first drive system, a second drive system, a transfer mechanism, and a clutch mechanism. The transfer system is configured to transfer and retrieve items to and from the destination areas, and the clutch mechanism is configured to engage and disengage the transfer mechanism from at least one of the motors, whereby the second drive system drives movement of the vehicle independently of the transfer mechanism.

REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of co-pending U.S. patentapplication Ser. No. 16/993,933 filed on Aug. 14, 2020, which claimspriority to U.S. Provisional Patent Application No. 62/886,602 filed onAug. 14, 2019. The present application claims priority to each of theforegoing applications and the entire disclosure of each of theforegoing applications is hereby incorporated by reference.

BACKGROUND OF THE INVENTION Field of the Invention

Embodiments of the present invention generally relate to automatedvehicles configured to perform inventory management tasks in awarehouse, storage and/or distribution environment.

Description of the Related Art

Modern material handling systems, such as those used in mail-orderwarehouses, supply chain distribution centers, and custom-ordermanufacturing facilities, face significant challenges in responding torequests for inventory articles. In their incipiency, enterprises willgenerally invest in a level of automation that is at least adequate forcurrent needs. As the scale of an inventory management system expands toaccommodate a greater number and variety of articles, however, so toodoes the cost and complexity of operating it to simultaneously completethe packing, storing, replenishment, and other inventory managementtasks for which it is intended.

Failure to efficiently utilize resources such as space, equipment, andmanpower in an inventory management facility results in lowerthroughput, longer response times, and a growing backlog of unfinishedtasks. Greater efficiency may often be achieved, for a time, byincrementally expanding the capacity of the facility's existingautomation infrastructure, particularly when that expansion follows awell-conceived plan for growth. Sooner or later, however, a point ofdiminishing returns is encountered. That is, the achievement of furthergains in capacity and/or functionality eventually becomes costprohibitive as compared to available alternatives, if such gains can berealized at all. When that point of diminishing returns is reached, afacility operator may be forced to abandon pre-existing materialhandling infrastructure and to replace that infrastructure with acompletely new automation platform.

SUMMARY OF THE INVENTION

In accordance with embodiments of the present disclosure, thedisadvantages and problems associated with conventional warehouseautomation approaches have been substantially reduced or eliminated byone or more vehicles configurable to perform a variety of tasks relevantto an inventory management operation. In embodiments, each vehicle isconfigured and operable to perform a first set of one or more inventorymanagement tasks. Examples of tasks each vehicle is configured toperform utilizing onboard resources include operating a transfermechanism of the vehicle to retrieve an inventory item to, and/orretrieve an inventory item from, a destination area of a vertical arrayof storage areas. For such tasks, each vehicle is configured to travelvertically—along a guide system bringing the vehicle to the appropriatedestination area—as well as horizontally upon, for example, asubstantially planar surface which extends between an array of storageareas and a remote location such, for example, as a pick station, apacking station, or even a second vertically array of storage areas.

In an embodiment, a vehicle configured to perform inventory managementtasks comprises a vehicle configured to perform inventory managementtasks in an inventory management handling system having a plurality ofdestination areas and a guide system, the vehicle comprising a platformdimensioned and arranged to receive an item to be at least one oftransferred to or received from one of the destination areas; aplurality of motors; a first drive system having a first plurality ofdrive elements configured to engage the guide system, by operation of afirst subset of the plurality of motors, to move the vehicle along avertical path segment extending between a support surface underlying thevehicle and one of the destination areas; a second drive system having afirst plurality of drive elements configured, by operation of a secondsubset of the plurality of motors, to engage the underlying supportsurface and drive movement of the vehicle in a non-vertical direction; atransfer mechanism configured to at least one of transfer an item fromthe platform to one of the plurality of destination areas or retrieve anitem from one of the plurality of destination areas; and a clutchmechanism configured to engage and disengage the transfer mechanism fromthe second subset of motors, whereby the second drive system drivesmovement of the vehicle independently of the transfer mechanism.

In some embodiments, the first subset of one or more motors comprises asingle motor configured to rotate the first plurality of drive elementsof the first drive system. In an embodiment, the second subset of motorscomprises a plurality of motors, wherein a first motor of the secondsubset drives rotation of a first drive element of the second drivesystem and a second motor of the second subset drives rotation of asecond drive element of the second drive system.

In some embodiments, the first plurality of drive elements of the firstdrive system includes a plurality of gears dimensioned and arranged tointeract with complementary teeth of the guide system to control theposition of the vehicle along the guide system. In such an embodiment,the first drive system may include a pair of drive axles, wherein thedriven gears are fixed to the drive axles so that the gears aresynchronously driven to drive the vehicle along the guide system.

In some embodiments, the second drive system includes a first driveelement driven by a first motor of the second subset to rotate about afirst axis of rotation, and a drive element driven by a second motor ofthe second subset to rotate about a second axis of rotation, whereineach of the first and second drive elements is dimensioned and arrangedto engage a respective portion of the underlying support surface formovement of the vehicle thereupon. In one such embodiment, the clutchmechanism comprises: a first pivotable carrier movable between a firstangular orientation relative to the platform and a second angularorientation relative to the platform. wherein the first drive element isrotatably coupled to the first pivotable carrier for angular movementtherewith; and a second pivotable carrier movable between the firstangular orientation and the second angular orientation, wherein thesecond drive element is coupled to the second pivotable carrier forangular movement therewith. The first and second axes of rotation areco-axial while the first and second pivotable carriers have a commonangular orientation.

Optionally, the second drive system further includes a first drivenelement rotatably coupled to the first pivotable carrier and a firstendless loop element for transferring rotary power to the first drivenelement; and a second driven element rotatably coupled to the secondpivotable carrier and a second endless loop element for transferringrotary power to the second driven element. Each of the first endlessloop element and the second endless loop element may include a belt. Insuch an embodiment, the second drive system further comprises a firstpulley, the first pulley and first drive element being driven by thefirst motor of the second subset, wherein the first pulley isdimensioned and arranged to engage the first endless loop element tothereby drive the first driven element; and a second pulley, the secondpulley and second drive element being driven by a second motor of thesecond subset of motors such that the pulley is dimensioned and arrangedto engage the second endless loop element to thereby drive the seconddriven element.

In the preceding embodiment, the clutch mechanism may further include athird driven element rotatably coupled to the first driven element andcoaxial therewith, the third driven element being dimensioned andarranged to drivingly engage a first portion of the transfer mechanismand thereby transfer power from the first motor of the second subsetwhile the first pivotable carrier is in the first angular orientation,as well as a fourth driven element rotatably coupled to the seconddriven element and coaxial therewith, the fourth driven element beingdimensioned and arranged to drivingly engage a second portion of thetransfer mechanism and thereby transfer power from the second motor ofthe second subset while the second pivotable carrier is in the firstangular orientation.

In embodiments, the second drive system further includes a plurality ofomnidirectional wheels dimensioned and arranged to frictionally engagerespective portions of the underlying surface to thereby support thevehicle. In one such embodiment, the second first drive system furtherincludes a plurality of drive axles, wherein at least a pair of theomnidirectional wheels is driven by at least one of the second subset ofmotors.

In any of the preceding embodiments, the vehicle may further comprise anonboard controller for directing operation of the plurality of motors,the controller including a processor and a memory containinginstructions, executable by the processor, to operate the motors of thesecond subset to drive the first and second drive elements of the seconddrive system to thereby displace the vehicle along a substantiallyhorizontal path upon the support surface. In one such embodiment, thememory contains instructions executable by the processor to operate thesecond subset of motors to bring respective portions of the first drivesystem into facing alignment with corresponding portions of the guidesystem and/or to initiate driving engagement of respective portions ofthe first drive system with corresponding aligned portions of theguiding system and thereby cause elevation or descent of the vehiclerelative to a datum plane.

In the preceding embodiment, the clutch mechanism may be configured toenable transmission of power, from the motors of the second subset, tothe transfer mechanism responsive to elevation of the vehicle to aposition above the datum plane. To this end, the memory furthercontaining instructions executable by the processor for operating amotor of the second subset of one or motors to cause the transfermechanism to one of transfer an item from the platform to a destinationarea adjacent the vehicle or to retrieve an item from the destinationarea to the platform. In such embodiment, the clutch mechanism isconfigured to disable actuation of the transfer mechanism responsive todescent of the vehicle to a position below the datum plane.

Another embodiment of a vehicle operable in an inventory managementsystem having a plurality of destination areas and a guide systemcomprises: a first motorized drive system configured to engage the guidesystem to guide movement of the vehicle along a vertical path segment; asecond motorized drive system dimensioned and arranged to maneuver thevehicle upon a surface while the first drive system is out of engagementwith the guide system; a clutch mechanism operative to engage and todisengage transmission of power to the transfer mechanism, whereby eachof the first drive system and second drive system is operableindependently of the transfer mechanism; and a transfer mechanismoperative to transfer an item between the vehicle and one of theplurality of destination areas; wherein the first motorized drive systemincludes first and second pairs of motor driven rotary elements, therotary elements of each pair being configured to interact with the guidesystem to control the position of the vehicle along the guide system.

In the preceding embodiment, each rotary drive element, of the first andsecond pairs of rotary drive elements, may be a gear having teethdimensioned and arranged to engage complementary teeth of the guidesystem as the vehicle changes elevation along the guide system. In onesuch embodiment, the first drive system further includes a pair ofsynchronous drive axles, wherein the driven gears are fixed to the axlesso that the gears are synchronously driven to drive the vehicle alongthe guide system. Optionally, the clutch mechanism is dimensioned andarranged to disengage the transfer mechanism as the vehicle descends toa position beyond the datum plane, thereby disabling actuation of thetransfer mechanism by the controller. In such an embodiment, the clutchmechanism may be configured to engage with the transfer mechanism as thevehicle ascends to a position above the datum plane, thereby enablingactuation of the transfer mechanism by the controller.

A vehicle operable in an inventory management system according to afurther embodiment comprises a first motor and a second motor, a firstpair of omnidirectional rollers and a second pair of omnidirectionalrollers, wherein a first omnidirectional roller of each pair isdimensioned and arranged to rotate about a first axis of rotation andwherein a second omnidirectional roller of each pair is driven by thefirst motor or the second motor for rotation about a second axis ofrotation; a fifth roller driven by the first motor or the second motor;and an actuator having an actuation surface configured to move from afirst position to a second position to selectively urge the fifth rollerin a direction toward an underlying support surface; wherein a surfaceof each of the first and second pairs of omnidirectional rollers, and asurface of the fifth roller are dimensioned and arranged to contact theunderlying support surface while the actuator is maintained in the firstposition, and wherein movement of the actuator into the second positioncauses a transfer of load from one or more of the omnidirectionalrollers to the fifth roller.

In some embodiments, the pair of motor driven omnidirectional rollersare driven independently of the second pair of motor drivenomnidirectional rollers.

In some embodiments, the actuator is a first actuator, wherein thevehicle further includes a sixth roller and a second actuator movablefrom a third position to a fourth position, and wherein movement of thefirst and second actuators into the second and fourth positions,respectively, causes a transfer of load from one or more of theomnidirectional rollers to the fifth and sixth rollers.

In the preceding embodiment, the vehicle further includes a platform anda transfer mechanism operative to at least one of transfer an item fromthe platform to a target surface or to retrieve an item from a targetsurface. Optionally, the vehicle of the preceding embodiment may furtherinclude a clutch mechanism operative to engage and disengage thetransfer mechanism.

A method of operating an automated vehicle, according to any of thepreceding embodiments, in an inventory management system having a rackstructure defining a plurality of destination areas and a guide systemcomprises operating a first motor to control rotation of a firstplurality of drive elements of the automated vehicle to move theautomated vehicle upon an underlying support surface and into apre-climb position wherein a second plurality of drive elements of theautomated vehicle are aligned with and engage the guide system;operating a second motor to control rotation of the second plurality ofdrive elements to advance the automated vehicle vertically along theguide system and into an elevated position of alignment with a firstdestination area of the plurality of destination areas; and engaging aclutch mechanism of the automated vehicle while operating the firstmotor to transmit power from the first motor to a transfer mechanism ofthe automated vehicle and thereby to transfer a container of inventoryitems from the first destination area onto a support surface of theautomated vehicle for subsequent transport of the container.

In addition or alternatively, a method of operating an automated vehicleaccording to any of the preceding embodiments comprises operating afirst motor to control rotation of a first plurality of drive elementsof the automated vehicle to move the automated vehicle upon anunderlying support surface and into a pre-climb position wherein asecond plurality of drive elements of the automated vehicle are alignedwith and engage the guide system; operating a second motor to controlrotation of the second plurality of drive elements to advance theautomated vehicle vertically along the guide system and into an elevatedposition of alignment with a first destination area of the plurality ofdestination areas; and engaging a clutch mechanism of the automatedvehicle while operating the first motor to transmit power from the firstmotor to a transfer mechanism of the automated vehicle and therebytransfer a container of inventory items from a support surface of theautomated vehicle into the first destination area. Other and furtherembodiments of the present invention are described below.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. The figures are not drawn to scale and may be simplifiedfor clarity. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1A is a perspective view depicting an inventory management systemwhich includes a plurality of automated guided vehicles that are eachconfigurable, by interaction with one or more functional accessorymodules, to perform a subset of inventory management tasks in support ofa parts picking process, according to one or more embodiments of thepresent disclosure;

FIG. 1B is a perspective view depicting an inventory management systemwhich includes a plurality of automated guided vehicles that are eachconfigurable, by interaction with a functional accessory module of afirst group of functional accessory modules, to perform a first subsetof inventory management tasks and, by interaction with a functionalaccessory module of a second group of functional accessory modules, toperform a second subset of inventory management tasks, according to oneor more embodiments of the present disclosure;

FIG. 1C is a perspective view depicting an inventory management systemwhich includes a plurality of automated guided vehicles that are eachconfigurable, by interaction with one or more functional accessorymodules of a first, second or third group of functional accessorymodules, to perform a first, second and/or third subset of inventorymanagement tasks, according to one or more embodiments of the presentdisclosure;

FIG. 2A is a perspective view depicting an automated guided vehicleconstructed in accordance with an exemplary embodiment of the presentdisclosure and adapted for use in any of the inventory managementsystems depicted in FIGS. 1A to 1C;

FIG. 2B is a top view of the exemplary automated guided vehicle depictedin FIG. 2A;

FIG. 2C is a bottom view of the exemplary automated guided vehicledepicted in FIG. 2A;

FIG. 2D is a forward elevation view of the exemplary automated guidedvehicle depicted in FIG. 2A;

FIG. 2E is a rear elevation view of the exemplary automated guidedvehicle depicted in FIG. 2A;

FIG. 2F is a side elevation view of the exemplary automated guidedvehicle depicted in FIG. 2A;

FIG. 2G is a top plan view depicting an automated guided vehicle in theprocess of retrieving a container of inventory items from a storage areaof a plurality of storage areas arranged in a vertical column, accordingto one or more embodiments;

FIG. 2H is a partial side elevation view, taken across line II-H in FIG.2G, to show actuation of a transfer mechanism in accordance with one ormore embodiments; and

FIG. 2I is an enlarged view of the partial side elevation view of FIG.2H to reveal a greater level of detail of an illustrative transfermechanism which may be used to transfer items from or to one of thestorage areas.

FIG. 3A is a forward elevation of the exemplary automated guided vehicleof FIGS. 2A-2F, taken in cross section across line IIIA-IIIA in FIG. 2A

FIG. 3B is bottom plan view of the exemplary automated guided vehicleFIGS. 2A-2F, with a clutch mechanisms thereof being partiallydisassembled to expose the internal construction thereof;

FIG. 4A is a side elevation view of the exemplary automated guidedvehicle of FIGS. 2A-2F, taken in cross section across line IVA-IVA inFIG. 2A;

FIG. 4B is a side elevation view of the exemplary automated guidedvehicle of FIGS. 2A-2F, taken in cross section across line IVA-IVB inFIG. 2A while the clutch mechanisms thereof are disengaged in accordancewith one or more embodiments;

FIG. 4C is a side elevation view of the exemplary automated guidedvehicle of FIGS. 2A-2F, taken in cross section across line IVB-IVB inFIG. 2A while the clutch mechanisms thereof are engaged in accordancewith one or more embodiments;

FIGS. 4D and 4E are side elevation views of the exemplary automatedguided vehicle of FIGS. 2A-2F, the lateral exterior cover plate beingomitted to reveal an optional actuator mechanism having a forceimparting member which is selectively movable between a first position(FIG. 4D) and a second position (FIG. 4E);

FIG. 4F is an enlarged view of the actuator mechanism depicted in FIGS.4D and 4E, the force imparting member thereof being shown in the first,non-force imparting position;

FIG. 4G is an enlarged view of the actuator mechanism depicted in FIGS.4D to 4F, the force imparting member thereof being shown in the second,force imparting position;

FIG. 5A is a front perspective view depicting the use of an automatedguided vehicle in conjunction with a functional accessory module of afirst group of functional accessory modules, according to one or moreembodiments;

FIG. 5B is a perspective view depicting pre-docking alignment of anautomated guided vehicle with a first illustrative base which may berealized either as an integral part of a functional accessory module, asany of the functional accessory modules shown in FIGS. 1A to 1C and 5A,or as a separate functional accessory module serving as an adaptorbetween the vehicle and at least one of those other types of functionalmodules, according to respective embodiments;

FIG. 5C is a perspective view depicting post-docking alignment of anautomated guided vehicle with a second alternative base which may berealized either as an integral part of a functional accessory module, asany of the functional accessory modules shown in FIGS. 1A to 1C and 5A,or as a separate functional accessory module serving as an adaptorbetween the vehicle and at least one of those other types of functionalmodules, according to respective embodiments;

FIG. 5D is a rear elevation view of an automated guided vehicle dockedwith a base such as depicted in FIG. 5C or 5D, where respective surfacesof each of the base and vehicle are in contact, at multiple points, withan underlying support surface;

FIG. 5E is a rear elevation view of the docked automated guided vehicleof FIG. 5D, after a first drive system of the vehicle has been actuatedto lift the base with which it is docked, such that none of the surfacesof the base are in contact with the underlying support surface;

FIG. 6A is a perspective view depicting post-docking alignment of anautomated guided vehicle with a third alternative base which may berealized either as an integral part of a functional accessory module, asone or more of the functional accessory modules shown in FIGS. 1A to 1Cand 5A, or as a separate functional accessory module serving as anadaptor between the vehicle and at least one or more of those othertypes of functional modules, according to respective embodiments;

FIG. 6B is a rear elevation view of the docked automated guided vehicleof FIG. 6A, after a first drive system of the vehicle has been actuatedto lift the base with which it is docked, such that none of its surfacesare in contact with the underlying support surface;

FIG. 6C is a perspective view of an inventory management system,depicting the placement and use of a plurality of functional accessorymodules constructed in accordance with any of the embodiments shown inFIGS. 5A to 6B;

FIG. 7A is a perspective view depicting pre-docking alignment of anautomated guided vehicle with a first functional accessory moduledimensioned and arranged serve as an adaptor between the vehicle and atleast one or more of the other types of functional modules shown inFIGS. 1A to 1C, according to respective embodiments;

FIG. 7B is a perspective view depicting post-docking alignment betweenthe semi-autonomous vehicle and the first functional accessory module ofFIG. 7A;

FIG. 7C is a rear elevation view of the docked automated guided vehicleand first functional accessory module of FIG. 7B, where respectivesurfaces of each of the vehicle and the first functional accessorymodule are in contact, at multiple points, with an underlying supportsurface;

FIG. 7D is a rear elevation view of the docked automated guided vehicleand first functional accessory module of FIG. 7B, after a first drivesystem of the vehicle has been actuated to lift the first functionalaccessory module, such that none of the surfaces of the first functionalaccessory module are in contact with the underlying support surface;

FIG. 8A is a partial elevation view depicting pre-docking alignment ofthe docked semi-automatic guided vehicle and first functional accessorymodule of FIG. 7D with a second functional accessory module, the secondfunctional accessory module being realized as a multi-level storage rackhaving surfaces dimensioned and arranged to support the rack upon theunderlying support surface in accordance with one or more embodiments;

FIG. 8B is a partial elevation view depicting post-docking alignment ofthe docked automated guided vehicle and first functional accessorymodule of FIGS. 7D and 8A with the second functional accessory module,after a first drive system of the vehicle has been actuated to furtherlift the first functional accessory module and also lift the secondfunctional accessory module, such that none of the surfaces of the firstor second functional accessory modules are in contact with theunderlying support surface.

FIG. 8C is a full elevation view depicting relative positions of thedocked automated guided vehicle, first functional accessory module, andsecond functional accessory module following lifting of the secondfunctional accessory module in the manner shown in FIG. 8B;

FIG. 9 is a partial perspective view depicting elements of an inventorymanagement system that includes respective groups of the first andsecond accessory modules with which automated guided vehicles areadapted to cooperate to perform corresponding subsets of inventorymanagement tasks, and also a group of third functional accessory moduleswith which the automated guided vehicles are adapted to cooperate toperform yet another subset of inventory management tasks, according toone or more embodiments;

FIGS. 10A and 10B are elevation view depicting docked alignment betweenan automated guided vehicle and one of the functional accessory modulesfrom the third group, but prior to activation of the first drive systemof the automated guided vehicle according to some embodiments;

FIG. 10C is an enlarged, partial elevation view taken from theperspective of FIG. 10A and depicting facing alignment of a rotaryelement of the first drive system with a corresponding portion of theguide system of a functional accessory module from the third group ofaccessory modules, according to one or more embodiments;

FIG. 10D is an enlarged partial elevation view taken from the sameperspective as FIGS. 10A and 10C, but after actuation, in a firstdirection, of respective rotary elements of the first drive system ofthe vehicle with corresponding facing portions of the guide system ofthe functional accessory module for lifting thereof, according to one ormore embodiments;

FIG. 10E is an elevation view taken from the same perspective as FIG.10B, but after actuation, in the first direction, of the rotary elementsof the first drive system with corresponding facing portions of theguide system of the functional accessory module for lifting thereof,according to one or more embodiments;

FIG. 10F is an elevation view taken from the same perspective as FIGS.10B and 10E, but after actuation, in a second direction, of respectiverotary elements of the first drive system of the vehicle withcorresponding facing portions of the guide system of the functionalaccessory module for setting the functional accessory module upon anunderlying support surface and, as shown, thereafter elevating thevehicle within the functional accessory module, according to one or moreembodiments;

FIG. 11A is a rear perspective view depicting deployment of a functionalaccessory module, such as the exemplary module depicted in FIGS. 10A to10F, to a flow rack structure dimensioned and arranged to supply itemssuch as fast moving commercial goods in a goods-to-picker inventorymanagement system, according to an illustrative embodiment;

FIG. 11B is a side elevation of the illustrative embodiment of FIG. 11B,just prior to docking of the functional accessory module with the flowrack structure in accordance with one or more embodiments;

FIG. 11C is a side elevation of the illustrative embodiment of FIGS. 11Aand 11B, subsequent to docking of the functional accessory module withthe flow rack structure and elevation of the vehicle within thefunctional accessory module into a position for transferring an itemfrom the vehicle to a target surface of the flow rack, according to oneor more embodiments;

FIG. 11D is a front perspective view of the illustrative embodiment ofFIGS. 11A to 11C, depicting elevation of the vehicle within thefunctional accessory module into the position shown in FIG. 11C,according to one or more embodiments;

FIG. 11E is a top plan view of the illustrative embodiment of FIGS. 11Ato 11D, depicting elevation of the vehicle within the functionalaccessory module into the position shown in FIGS. 11C and 11D, accordingto one or more embodiments;

FIG. 11F is an enlarged top plan view of the illustrative embodiment ofFIGS. 11A to 11E, during transfer of an container from a surface of theflow rack structure of FIG. 11E to the platform of the elevated vehicle,as part of a dynamic reallocation of inventory in accordance with one ormore embodiments consistent with the present disclosure;

FIG. 11G is a top plan view depicting of the illustrative embodiment ofFIGS. 11A to 11F, depicting the transfer of items from one vehicle toanother vehicle using FAMs, as part of a dynamic allocation of inventoryaccording to one or more embodiments consistent with the presentdisclosure;

FIG. 11H is a rear elevation view depicting the completion of one ormore inventory management tasks, by vehicles and at least one FAM, torealize a dynamic allocation of inventory, according to one or moreembodiments;

FIG. 11I is a rear elevation view showing, after the functionalaccessory module has docked with the flow rack, elevation of the vehiclewithin module to a position suitable for transfer of an item, accordingto one or more embodiments;

FIG. 12 is a partial perspective view depicting a part of an inventorymanagement system, which may form part of the system shown in FIG. 1C,which utilizes automated guided vehicles to transfer containers ofinventory items back and forth between a picking area and a plurality ofstorage locations, according to one or more embodiments;

FIG. 13A is a front elevation view depicting a plurality of automatedguided vehicles being operated to perform various item replenishmentand/or item retrieval tasks as part of the inventory management systemof FIG. 12 , according to one or more embodiments;

FIG. 13B is a side elevation view depicting a plurality of automatedguided vehicles being operated to perform various item replenishmentand/or item retrieval tasks as part of the inventory management systemof FIG. 12 , according to one or more embodiments;

FIG. 13C is a top plan view depicting a plurality of automated guidedvehicles being operated to perform various item replenishment and/oritem retrieval tasks as part of the inventory management system of FIG.12 , according to one or more embodiments;

FIG. 13D is an enlarged side elevation view of the structure of FIG.13B, depicting an exemplary vertical support and guide system accordingto one or more embodiments;

FIG. 13E is an enlarged elevation view depicting a guide system segmentfor use in rack structures according to one or more embodiments;

FIG. 14A is a block schematic view depicting the allocation ofFAM-assisted inventory management tasks among a plurality of vehicles,by a controller, according to one or more embodiments;

FIG. 14B is a block diagram depicting the subsystems of a plurality ofguided vehicles according to one or more embodiments;

FIG. 14C is a block schematic diagram of a controller which may be usedto coordinate the assignment and performance of inventory managementtask activities by a plurality of vehicles and FAMs, in accordance ofone or more embodiments consistent with the present disclosure;

FIG. 15 is a flow chart depicting a process by which inventorymanagement tasks may be assigned to one or more vehicles and FAMs,according to one or more embodiments;

FIG. 16 is a flow chart depicting a process by which inventory items maybe dynamically allocated among various storage areas over a series ofconsecutive inventory management intervals, according to one or moreembodiments; and

FIG. 17 is a flow chart depicting a process by which an automated guidedvehicle performs inventory management tasks using only the onboardresources and capabilities of the vehicle, according to a first mode ofoperation and, according to a second mode operation, supplements theresources of the vehicle using the additional resources and capabilitiesof one or more FAMs.

While the systems and methods are described herein by way of example forseveral embodiments and illustrative drawings, those skilled in the artwill recognize that systems and methods for performing respectivesubsets of inventory management tasks using corresponding functionalaccessory modules are not limited to the embodiments or drawingsdescribed. It should be understood, that the drawings and detaileddescription thereto are not intended to limit embodiments to theparticular form disclosed. Rather, the intention is to cover allmodifications, equivalents and alternatives falling within the spiritand scope of the systems and methods for performing respective subsetsof inventory management tasks using corresponding functional accessorymodules defined by the appended claims. Any headings used herein are fororganizational purposes only and are not meant to limit the scope of thedescription or the claims. As used herein, the word “may” is used in apermissive sense (i.e., meaning having the potential to), rather thanthe mandatory sense (i.e., meaning must). Similarly, the words“include”, “including”, and “includes” mean including, but not limitedto.

DETAILED DESCRIPTION OF EMBODIMENTS

Various embodiments of a method and apparatus for performing inventorymanagement tasks in an inventory management system are described. In thefollowing detailed description, numerous specific details are set forthto provide a thorough understanding of claimed subject matter. However,it will be understood by those skilled in the art that claimed subjectmatter may be practiced without these specific details. In otherinstances, methods, apparatuses or systems that would be known by one ofordinary skill have not been described in detail so as not to obscureclaimed subject matter.

Some portions of the detailed description that follow are presented interms of algorithms or symbolic representations of operations on binarydigital signals stored within a memory of a specific apparatus orspecial purpose computing device or platform. In the context of thisparticular specification, the term specific apparatus or the like mayinclude a general-purpose computer once it is programmed to performparticular functions pursuant to instructions from program software.Algorithmic descriptions or symbolic representations are examples oftechniques used by those of ordinary skill in the signal processing orrelated arts to convey the substance of their work to others skilled inthe art. An algorithm is here, and is generally, considered to be aself-consistent sequence of operations or similar signal processingleading to a desired result. In this context, operations or processinginvolve physical manipulation of physical quantities. Typically,although not necessarily, such quantities may take the form ofelectrical or magnetic signals capable of being stored, transferred,combined, compared or otherwise manipulated. It has proven convenient attimes, principally for reasons of common usage, to refer to such signalsas bits, data, values, elements, symbols, characters, terms, numbers,numerals or the like. It should be understood, however, that all ofthese or similar terms are to be associated with appropriate physicalquantities and are merely convenient labels.

Unless specifically stated otherwise, as apparent from the followingdiscussion, it is appreciated that throughout this specificationdiscussions utilizing terms such as “processing,” “computing,”“calculating,” “determining” or the like refer to actions or processesof a specific apparatus, such as a special purpose computer or a similarspecial purpose electronic computing device. In the context of thisspecification, therefore, a special purpose computer or a similarspecial purpose electronic computing device is capable of manipulatingor transforming signals, typically represented as physical electronic ormagnetic quantities within memories, registers, or other informationstorage devices, transmission devices, or display devices of the specialpurpose computer or similar special purpose electronic computing device.

Reference will now be made in detail to exemplary embodiments of thepresent invention; examples of which are illustrated in the accompanyingdrawings. Wherever possible, the same reference numbers will be usedthroughout the drawings to refer to the same or like parts.

Embodiments consistent with the present disclosure include one or moreautomated guided vehicles configurable to perform a variety of tasksrelevant to an inventory management operation. To maintain a high degreeof modularity, vehicles constructed according to some embodiments of thepresent disclosure are configured and operable to perform a first subsetof one or more inventory management tasks and, in order to performfurther subsets of one or more inventory management tasks, to interactwith any of a plurality of interchangeable, functional accessory modules(FAMs). In embodiments, a subset of the FAMs are vertically andhorizontally displaceable, such that they can be moved, as needed, todifferent locations within an inventory management facility. Thefacility may be, for example, a distribution center where items ofinventory are stored for subsequent shipment to retail store locationsand/or a fulfillment center where items of inventory are shippeddirectly to retail customers.

Each FAM of a group of FAMs has at least one function, capability orphysical attribute which is missing in the vehicles and in the FAMs of adifferent group. In embodiments, the vehicles and the FAM(s) cooperatesynergistically to perform various tasks according to the manner inwhich each vehicle is operated and the specific FAM(s) with which thatvehicle is paired at a given time. By replacing one FAM or set of FAMswith one or more other FAMs, any of the vehicles can be readilyconfigured to perform an alternate, or an additional, set of inventorymanagement tasks. Accordingly, the vehicles retain their utility in aninventory management system even as the complexity of that systemincreases to achieve further inventory differentiation (e.g.,accommodate a higher SKU count), higher order picking volumes, and/orgreater throughput requirements.

As will be described in greater detail later, an association ofindeterminate duration is formed between a vehicle and one or more ofthe FAMs to enable the performance of a second subset of one or moreinventory management tasks. In some cases, all of the functionalityrequired for completion of the second subset of inventory managementtask(s) is obtained by the combination of a vehicle and a single orfirst FAM. In embodiments, the association formed between the first FAMand a vehicle is achieved by a direct engagement of one or morecomponents of the vehicle with one or more components of the FAM. Inother cases, the performance of the second subset of one or moreinventory management tasks further requires the use of an additional orsecond FAM. In embodiments, the second FAM performs the function of anadaptor between the vehicle and the first FAM. According to embodiments,the association between any or all of a vehicle and any associatedFAM(s) is terminated once the assigned subset of inventory managementtasks is completed and/or the use of any or all of these components arerequired for some other task(s).

Order picking systems, be they mail-order or e-commerce warehouses,supply chain distribution centers, cross dock facilities, custom-ordermanufacturing facilities, or any other type of inventory system, aregenerally distinguished from one another according to: (i) who and/orwhat picks the items; (ii) who and/or what moves within the pickingarea; (iii) whether the different picking zones are connected byconveyors; and (iv) what picking policy is being applied. Availablepicking systems include picker-to-parts, pick-to-box, pick-and-sort,parts-to-picker, and completely automated picking. The level ofautomation required for implementation increases gradually as the orderpicking system moves from picker-to-parts to completely automatedpicking systems.

The most basic order picking system in use today is the picker-to-partssystem. Here, human pickers walk (or drive) along the aisles andmanually pick items from the storage locations. In a low-level pickingsystem, the items are stored in storage racks or bins that can be easilyreached by the picker. In a high-level picking system, the picker uses alifting truck or crane to reach items stored in elevated storage racks.Picker-to-parts systems of either type are easy to implement, modify andscale, but their use is usually limited to applications where both thepick volume and the inventory item (e.g., SKU) count are low. Thislimitation is due to the sharp drop in productivity that comes withincreases in travel time.

A zone pick system is similar to the picker-to-parts system in thatpicking activity is performed by human pickers. However, the area withinwhich these workers conduct their picking is divided into discretezones. These picking zones are connected by conveyors. Orders are pickedsequentially, by zone and then they are sorted according to destination.Each customer order typically corresponds to one picking box, which ispassed on to the next zone as soon as all required items are picked inthe current zone. An efficient pick-to-box system is one in which theworkload is balanced among the various picking zones. Pick-to-boxsystems are often used in situations where there are many small-sizeditems in inventory but the orders themselves are typically only a fewitems in number.

FIG. 1A is a perspective view depicting an inventory management system10 which includes a plurality of autonomous or automated guided vehicles12. Each vehicle 12 is configurable, by interaction with one or morefunctional accessory modules (FAMs), to perform a subset of inventorymanagement tasks in support of a parts picking process, according to oneor more embodiments of the present disclosure. In the illustrativeembodiment of FIG. 1A, inventory management system 10 implements a“picker-to-parts” scheme or, alternatively, a zone scheme. In eithercase, items of inventory (not shown) are stored in, and retrieved from,storage racks indicated generally at 14. Storage racks 14 define rowsand columns of storage cells which are dimensioned and arranged toreceive item-containing bins 16. The bins are at a low enough heightthat they can be easily reached by human picker P₁.

As an incremental advance over a picker-to-parts system or picker-to-boxapproach which already utilizes low-level storage racks 14 and bins 16,implementation of the inventory management system 10 shown in FIG. 1Amay be implemented solely by the addition of vehicles 12, and aplurality of FAMs 18 which, collectively, form a first group of FAMs.Each FAM 18 of the first group includes a base 20, a vertical support orstalk 22 extending in an upward direction from base 20, and a pluralityof item storage cells 24 mounted on stalk 22. In the embodiment of FIG.1A, a user terminal having a touchscreen display 26 is also mounted onstalk 26 to accommodate presentation of various instructions to thepicker(s) and permit the entry of confirmatory acknowledgements inaccordance with one or inventory management tasks to be performed byeach FAM 18. In some embodiments, the same picker who transfers itemsfrom one of racks 14 into one of the FAMs 18 accompanies that FAM to apacking station, as station S1 or S2. At the packing station, the itemsare transferred into a vehicle for shipment.

For implementation of a zone pick scheme utilizing vehicles 12 and FAMs18, items are removed from inventory and placed in one or more storagecells 24, of a selected FAM 18, by a picker operating in a first storagearea. The selected FAM 18 then travels unaccompanied by the picker to asecond storage area (not shown). At the second storage area, anotherpicker removes additional items from inventory and transfers the itemsinto the one or more storage cells of the selected FAM 18. FAMs 18 arethus configurable to perform the function of a conveyor connectingdifferent picking zones.

The FAMs 18, in conjunction with vehicles 12, are also operative toperform inventory management tasks consistent with a pick-and-sortapproach, also known as a wave picking system. A wave pickingarrangement consists of one or more picking area(s) and one or moresorting area(s). Inventory items associated with multiple customerorders are picked in batches. After picking, the batches of items may beput in respective FAMs 18, rather than a transport conveyor, such thatthe FAMs 18 bring the picked items to a sorting area (not shown).Pick-and-sort systems are normally operated in picking waves, where allorders are sorted before the next wave is released.

Turning now to FIG. 1B, there is shown a perspective view of aninventory management system 30 that, for purposes of illustrativeexample only, incorporates pre-existing elements of the inventorymanagement system 10 shown in FIG. 1A, according to one or moreembodiments. Specifically, the inventory management system 30 retainsthe vehicles 12 formerly included in the arrangement shown in FIG. 1Aand, optionally, further incorporates the storage racks 14, bins 16, andpreviously acquired FAMs 18 of the first group of FAMs. The inventorymanagement system of 30 of FIG. 1B further includes a plurality ofadditional FAMs, such as FAMs 40 of a second group of FAMs and FAMs 50of a third group of FAMs. As will be explained in greater detail later,vehicles 12 are configured to interact with FAMs 40 and 50,respectively, to synergistically perform subsets inventory managementtasks which are different from those performed through interactions withone of FAMs 18.

In the picking of articles for order fulfillment, a distinction is madebetween two types of articles, namely fast moving and slow-moving.Fast-moving articles are those units of inventory which are neededfrequently and/or in larger quantities. Slow-moving articles, on theother hand, are those articles of inventory which are needed rarely orin small quantities. It is possible for an article to move from one ofthese two categories to the other. The movement may be bidirectionaldue, for example, to a cyclicality in consumer demand according to thetime of year (e.g., back-to-school, seasonal items, holiday sales, etc).In some cases, a newly introduced product in inventory may experiencesuch a high rate of growth in demand that the product enters and remainsin the fast-moving category for an extended period time. Contrarily, ashift into the slow moving category may portend a permanent decline inthe popularity of a mature product. The ability to deploy additionaland/or different types of FAMs as needed, as exemplified by theillustrative inventory management system 30 of FIG. 1B, allows awarehouse or distribution center facility operator to dynamically adaptto both short and long term shifts in demand for inventory items.

In the embodiment depicted in FIG. 1B, inventory management system 30includes a plurality of multi-level storage racks indicated generally at60. The storage racks 60 define a plurality of storage surfacesindicated generally at 62, 64, and 66. Each of the FAMs 40 includes abase 42 which is dimensioned and arranged to fit under any of the racks60, and to be placed there by one of the vehicles 12 with which it isdocked. In a manner to be described shortly, each vehicle 12 is operableto lift the FAM 40 with which it is docked and, as well, to lift therack 60 under which that FAM 40 is positioned. A vehicle 12 paired witha FAM 40 is further operable to transport a lifted rack 60, for example,from one of the positions occupied by racks 60 a, 60 b, or 60 c, to oneof the positions adjacent picking area P, presently occupied by racks 60d, 60 e, and 60 f.

With continuing reference to FIG. 1B, it will be seen that vehicle 12 ais depicted as being docked with rack 60 f where they can be accessed bya picker. Others of the racks 60, as racks 60 a, 60 b, and 60 c, areshown as having been deposited, by execution of appropriate inventorymanagement tasks by vehicles 12 and FAMs 40, into a storage areacomprising a symmetrical arrangement of rows separated by aisles throughwhich the vehicles can pass. Arranging racks 60 which already have itemsof inventory deposited on the storage surfaces thereof in such a compactmanner allows any of the racks 60 to be transferred, by one of thevehicles, as vehicle 12 a in association with one of the FAMs 40, to apicking or, alternatively, a sortation area (not shown) when they areneeded to fulfill a requirement for that item, as in an orderfulfillment process. In some embodiments, the rows of racks as racks 60a, 60 b and 60 c serve as a buffer area from which a steady, andperiodically refreshed, flow of inventory containing racks are retrievedand presented to one or more nearby picking and/or sortation areas. Thenumber of racks in such a buffer area may increase or decrease inaccordance with fluctuations in order volume. Alternatively, or inaddition, additional racks 60 may be arranged in one or moreaisle-separated rows at a locations further away from the picking and/orsortation area(s), in accordance with the relative frequency of demandfor the items of inventory maintained in such racks.

As noted previously, the illustrative inventory management system 30depicted in FIG. 1B further includes FAMs of a third group of FAMs, withthe FAMs of the third group being indicated generally at 50, as well asa plurality of multi-level storage racks indicated generally at 60. Thestorage racks 60 define a plurality of storage surfaces indicatedgenerally at 62, 64, and 66. Each of the FAMs 40 includes a base 42which is dimensioned and arranged to fit under any of the racks 60, andto be placed there by one of the vehicles 12 with which it is docked. Ina manner to be described shortly, each vehicle 12 is operable to liftthe FAM 40 with which it is docked and, as well, to lift the rack 60under which that FAM 40 is positioned. A vehicle 12 paired with a FAM 40is further operable to transport a lifted rack 60, for example, from oneof the positions occupied by racks 60 a, 60 b, or 60 c, to one of thepositions adjacent picking area P, presently occupied by racks 60 d, 60e, and 60 f.

In the embodiment depicted in FIG. 1B, inventory management system 30further includes a multi-level flow rack structure, indicated generallyat 70. Flow rack 70 may, for example, be used to accommodate inventoryitems which are withdrawn from inventory at higher volumes than theitems stored in racks 60. In an embodiment, one or more levels of theflow rack structure 70, as upper levels 72 and 74, are configured asconveyors which are selectively actuated as needed to move inventoryitems forwardly into positions closest to the pick and/or sort stationoperator(s). As noted previously, the illustrative inventory managementsystem 30 further includes FAMs of a third group of FAMs, with the FAMsof the third group being indicated generally at 50.

In embodiments, and as will be explained in greater detail shortly, thevehicles 12, as vehicle 12 b, are dimensioned and arranged to dock with,lift, and transport any of the FAMs 50 for the purpose of replenishingflow rack structure 70. To that end, each FAM 50 defines an interiorcolumn dimensioned and arranged to enable any of vehicles 12, while inthe position shown occupied by vehicle 12 b, to move vertically (up ordown) within the FAM 50. Such movement enables the vehicles 12 to climbto a level within any FAM 50 that is aligned within one of the storagelevels of the rack structure 70. Once such alignment is achieved, eachvehicle is operable, to perform an inventory transfer task wherein acontainer, or case, of items or, in other embodiments, a pallet load ofitems, are transferred from a surface of the vehicle 12 to a storagelevel of the rack structure 70 with which that vehicle surface isaligned. In FIG. 1B, vehicle 12B is shown as being in the process oftransporting a first of the FAMs 50 along a path parallel to the rackstructure 70. Another of the FAMs 50 is shown in an interlockedalignment with rack structure 70, the vehicle therein ready to initiatethe process of lifting and transferring a case 76 into flow rackstructure 70.

Turning now to FIG. 1C, there is shown a perspective view of aninventory management system 100 that, for purposes of illustrativeexample only, incorporates pre-existing elements of the inventorymanagement system 30 shown in FIG. 1B, according to one or moreembodiments. Specifically, the inventory management system 100 retainsthe vehicles 12 formerly included in the arrangement shown in FIG. 1Aand, optionally, further incorporates the FAMs 40 and 50, the portablestorage racks 60, and the flow rack structure 70. Some of the vehicles12 are utilized as part of a storage and retrieval assembly or SAR whichalso includes an array of destination areas or storage locations 110.The storage locations 110 are arranged in columns. As will be explainedin greater detail later, the SAR of system 100 includes a guiding systemsuch, for example, as a track (not shown), to guide the vehiclesvertically in order to reach an intended one of the storage locations.

One of the inventory management tasks assigned to a vehicle 12 operatingas part of the SAR portion is to retrieve items from the storagelocations 110. This task can be viewed as a series of sub-tasks whichinclude exiting the current or starting location of the vehicle,traversing a path which takes the vehicle between the starting locationto an intermediate destination adjacent a point of entry into the arrayof storage locations and, at the intermediate destination, aligning thevehicle 12 with the point of entry. As a further sub-task of theretrieval task, the aligned vehicle enters the array and maintains itsalignment until it reaches the column within which the vehicle is,operated to climb, according to yet another sub-task, until it reaches atarget one of the storage areas 110. As further sub-tasks of theretrieval process, a transfer mechanism of the vehicle is operated toretrieve an item, descend within the column until the vehicle rests upona support surface, and then exit the array of storage location. As afinal sub-task of the retrieval operation, the vehicle 12 proceeds alonga path to output station 120, where an operator can retrieve the itemfrom the vehicle.

In one or more embodiments, the vehicle may perform a powerreplenishment task before returning, to a storage area, any remainingitems that were not retrieved by the operator. In this regard, thevehicle may merely re-perform the series of subtasks for retrieving anitem, except that instead of operating the transfer mechanism of thevehicle to retrieve an item at the target storage location, the transfermechanism is instead operated to transfer the item from a platform ofthe vehicle into the target storage location. If sufficient powerremains after a transfer, the vehicle may advance to another storagearea to obtain the next item to be retrieved. In this way, the system100 includes a plurality of individually controlled vehicles, asvehicles 12, that move up and down along tracks within any of aplurality of columns to retrieve items from the various storage areasand present the items to an operator before returning any remainingitems and then retrieving another item.

For ease of explanation, the vehicles 12 which cooperate as part of theSAR have been described as delivering and/or retrieving items to andfrom storage areas 110. The items may be configured so that anindividual item is stored at a storage location. However, in a typicaloperation environment, the items are stored in or on a storagemechanism, such as a container or platform. For instance, the items maybe stored in a container, referred to as a tote. The tote may be similarto a carton or box without a lid, so that an operator can easily reachinto the tote to retrieve an item at the picking station. Although thepresent system is described as using totes, it should be understood thatany of a variety of storage mechanisms can be used, such as pallets orsimilar platforms.

The storage locations 110, of the illustrative system 100 depicted inFIG. 1C, can be any of a variety of configurations. For instance, thesimplest configuration is that of shelves for supporting the items orthe container holding the items. Similarly, the storage locations 100may include one or more brackets that cooperate with the storagemechanism to support the storage mechanism in the storage location. Forexample, in the present instance, the storage locations include bracketssimilar to shelf brackets for supporting one of the totes, as depictedin FIG. 1C.

A subset of the vehicles 12 are thus configurable to perform a subset ofinventory management tasks relating to the storage and retrieval of itemcontaining totes T from storage areas 110, and to the delivery of thetotes T to the delivery station(s) 120 where an operator can retrieveone or more items from the totes. While the preceding description wasthat of a single vehicle performing all of the sub-tasks which comprisea retrieval task, in accordance with one or more embodiments, it isalternatively possible for sub-tasks of a given task to be distributedamong a plurality of vehicles 12. For example, a first vehicle exitingthe array of storage areas 110 may transfer an item it has retrieved toa second vehicle which, in turn, completes the retrieval task bydelivering the item to the delivery station(s) 120. After the operatorretrieves the items, the same vehicle or yet another of vehicles 12advances the tote T away from delivery station 120 and returns the toteto the same or a different one of the storage locations 110.

From the foregoing high-level description of FIGS. 1A to 1C, it will beappreciated that the vehicles 12 are operable in some modes of operationto synergistically cooperate with one or more FAMs to perform varioussets of inventory management tasks and, in other modes of operation, toperform other inventory management tasks which do not require anassociation with any of the FAMs as FAMs 30, 40 and 50. The manner inwhich such functionality is realized by will now be described byreference to FIGS. 2A-2I, which depict embodiments of automated guidedvehicles consistent with the present disclosure and, thereafter, otherfigures which depict exemplary configurations of the FAMs themselves.

Vehicles

Referring now to FIGS. 2A to 2I, there is shown an automated guidedvehicle 200 constructed in accordance with embodiments of the presentdisclosure and adapted to perform inventory management tasks in, forexample, any of the material handling systems depicted in FIGS. 1A to1C. Each delivery vehicle is an automated guided vehicle having a firstmotorized drive system and a second motorized drive system, as well asan onboard power supply. For use with an array of storage areas arrangedin columns and accessible by a guide system, as exemplified by storageareas 110 of FIG. 1C, the first motorized drive system of one or moreembodiments cooperates with a guide system to guide movement of thevehicle along respective vertical path segments adjacent respectivecolumns of storage areas. In such embodiments, the second motorizeddrive system is dimensioned and arranged to maneuver the vehicle 200upon an underlying support surface while the first drive system is outof engagement with the guide system. Typically, the underlying supportsurface is defined by one or more areas of a warehouse floor and/or oneor more elevated platforms within such a warehouse, or some combinationof these.

Each vehicle includes a transfer mechanism 210 operative to transfer anitem, for example, between a platform surface of the vehicle and one ofthe plurality of destination areas 110. As best seen in FIG. 2A, theplatform surface in this instance is defined by the exterior surfaces ofa plurality of rollers, indicated generally at 211. As will be explainedin greater detail later by reference to FIGS. 4B and 4C, each vehicle200 may optionally include a clutch mechanism operative to engage and todisengage transmission of power from a motor of the first or seconddrive systems to the transfer mechanism such that the transfer mechanismcan be operated, as needed, only while the first and second drivesystems are not being operated to propel the vehicle.

The vehicle 200 may incorporate any of a variety of mechanisms forloading an item onto the vehicle and for unloading the item from thevehicle into one of the storage areas. Additionally, the transfermechanism 210 may be specifically tailored for a particular application.In the present instance, the transfer mechanism 210 comprises one ormore displaceable element(s) configured to engage an item stored at astorage location and pull the item onto the vehicle. More specifically,in the present instance, the vehicle includes one or more displaceableelement(s) configured to move toward a tote in a storage location. Afterthe displaceable element(s) engage the tote, each displaceable elementis displaced away from the storage location, thereby pulling the toteonto the vehicle 200.

Referring to FIGS. 2A, 2B, and 2G to 2I in the present instance, thetransfer mechanism 210 comprises two endless carriers such as a drivebelt or, as shown, drive chains 214 a and 214 b 1. Along each endlesscarrier, as chains 214 a and 214 b, there is mounted a displaceableelement in the form of a displaceable pin 212 a or 212 b (FIGS. 2B, 2D,2E). Each pin, as pin 212 a extends inwardly toward the longitudinalcenter line of the vehicle. Optionally, a tubular bar element (notshown) may receive each of pins 212 a and 212 b and extend across thewidth of the vehicle 200.

In this instance, one or more motors of the second drive system drivesthe chains to selectively move the chains and pins 212 a and 212 btoward or away from storage locations. For example, as the vehicleapproaches a storage location to retrieve a tote T (FIGS. 2G to 2I), thechains may drive the displaceable pins 212 a and 212 b toward thestorage location so that the pins (and bar connecting the pins, ifpresent) underlie a groove or notch in the bottom of the tote. Thevehicle travels a small distance upward until the pins 212 a and 212 b(or bar) are disposed with the groove or notch, as best shown in FIG.2I. The chain then reverses so that the pins 212 a, 212 b move away fromthe storage location 100. Since the pins engage tote T within the notch,as the pins moves away from the storage location, the tote is pulledonto a surface of the vehicle. In this way, the transfer mechanism 210is operable to retrieve items from a storage location. Similarly, tostore an item in a storage location as location 110 in FIG. 1C, thechains 214 a, 214 b of the transfer mechanism 210 drives the pins 212toward the storage location until the item is in the storage location.The vehicle then moves downwardly to disengage the pins from the tote,thereby releasing the tote.

In the preceding description, transfer mechanism 210 has been describedas comprising endless carriers, in the form of chains 214 a and 214 b,and corresponding displaceable pin elements 212 a and 212 b, which mayoptionally be interconnected by a single tubular element. Such anarrangement is well suited to the retrieval of item-containing totesfrom storage areas arranged in a vertical column, wherein the tubularelements and/or a rod extending therebetween fits within a notch in anunderside of a tote proximate a leading edge thereof. In one or moreembodiments, the totes are placed in respective zones of an n-deepstorage cell, where n represents a maximum number of totes which can beaccommodated one behind another, within a substantially horizontalplane, when all totes are coupled together and disposed in a singlen-deep cell. FIG. 1C depicts a vertical array of such storage areas orcells, indicated generally at 110.

In this instance, and as best seen in FIG. 2H, two or more totes astotes T₁ and T₂ are coupled and decoupled from one another using matingconnectors indicated generally at 283 a and 283 b, respectively. TotesT₁ and T₂ are coupled and decoupled from one another through a series oflifting and separating movements implemented by movement of the vehicle210. As well, the transfer mechanism 210 is actuated by the second drivemechanism to pull a forward facing (“lead”) tote onto rollers 211 (FIG.2G) so as to be fully supported by vehicle 200. This pulling motionadvances the trailing tote (i.e., the one that is immediately behind thelead tote) into the aisle facing location. The first drive mechanism ofvehicle 200 is then operated briefly so that the vehicle 200 travels avertical distance sufficient to uncouple the lead tote from the trailingtote(s). Once decoupling is completed, the second drive system isbriefly operated again, this time centering the tote upon the vehicle200 such that the vehicle and tote is fully maneuverable, vertically,within the column.

In the illustrative embodiment depicted in FIGS. 2A and 2D to 2F, thefirst drive system of vehicle 200 includes four wheels in the form ofgears 220 that are driven to transport the vehicle along tracksdisposed, as will be described in greater detail later, along tracksdisposed within columns adjacent to the storage areas 110. The wheels220 are mounted onto two parallel spaced apart axles, as axle 215depicted in FIG. 2F, so that two of the wheels are disposed along theforward edge of the vehicle and two of the wheels are disposed along therearward edge of the vehicle.

With particular reference to FIGS. 2C and 2F, FIG. 2C is a bottom viewof the vehicle 200 depicted in FIG. 2A, while FIG. 2F is a sideelevation view of the vehicle depicted in FIG. 2A. As best seen in FIG.2C, vehicle 200 further includes a second drive system which isdimensioned and arranged to propel vehicle 200 upon an underlyingsupport surface—such as the floor of a warehouse or distribution center.In the illustrative embodiment of FIG. 2C, the second drive systemincludes a second motor of vehicle 200, indicated generally at 250 a,and a third motor of vehicle 200, indicated generally at 250 b. Thesecond motor and third motor, then, are first and second motors of asecond subset of a plurality of motors. By dynamically controlling therelative speed and/or direction of rotation of each of motors 250 a and250 b, vehicle 200 can be driven in any direction upon an underlyingsupport surface, as surface S depicted in FIG. 2F.

With continued reference to FIG. 2C, it will be seen that the seconddrive system of vehicle 200 includes a first drive element 252 a drivenby second motor 250 a to rotate about a first axis of rotation A₁, and asecond drive element 252 b driven by third motor 250 b to rotate about asecond axis of rotation A₂. Each of the first and second drive elements252 a and 252 b is respectively dimensioned and arranged to engage arespective portion of underlying support surface S for movement of thevehicle thereupon. In embodiments of a vehicle exemplified by FIGS. 2Cand 2F, the first axis of rotation A₁ and the second axis of rotation A₂are co-axial while drive elements 252 a and 252 b are supported by aplanar, horizontal surface. In this instance, the second drive system ofvehicles 200 further includes a plurality of omnidirectional wheelscomprising a first pair of wheels 254 a and 254 b and a second pair ofwheels 256 a and 256 b. The omnidirectional wheels are dimensioned andarranged to frictionally engage respective portions of the underlyingsurface S (FIG. 2F), with each of wheels 254 a, 254 b, 256 a and 256 bbeing secured to a corresponding drive axle as axles 258 a and 258 b,respectively.

With particular reference to FIGS. 2C and 2D to 2F, it will be seen thatthe vehicle 200 may also incorporate a series of guides, indicated at233, which downwardly depend from shafts 235. Each of the guides 233 isrotatably mounted to the lower part of a shaft 235. The inventors hereinhave determined that in some applications, the guides 233 facilitatealignment of vehicle 212 as it is maneuvered upon an underlying supportsurface and brought into alignment with one or more other structures itmay enter in the course of performing an assigned inventory managementtask. In FIG. 2C, for example, it can be seen that some of the guides233 are arranged along a longitudinal center line L of vehicle 200. FIG.2E depicts alignment of the guides 233 within a pair of parallel rails,shown in cross section and mounted upon underlying support surface S. Inan exemplary application, rails R₁ and R₂ are arranged along a path bywhich vehicle 200 enters, exits, and/or maneuvers beneath a verticalarray of storage cells, as depicted in FIGS. 12 to 13C.

Turning now to FIGS. 3A and 3B, FIG. 3A is a forward elevation view ofthe exemplary automated guided vehicle of FIGS. 2A-2F, taken in crosssection across line IIIA-IIIA in FIG. 2A, and FIG. 3B is bottom planview of the exemplary automated guided vehicle FIGS. 2A-2F. As best seenin FIG. 3A, the first drive system further includes a pair of inneridler pulleys 224 a, 224 b, and a pair of outer pulleys 222 a, 222 bthat, when driven by respective belts 226 a, 226 b, cause the gearedwheel 220 mounted on the same shaft to rotate and thereby propel thevehicle 200 in a vertical direction within a column (along the drivesurfaces of the track). The idler pulleys 224 a and 224 b rotate freelyrelative to the axles and maintain the tension of the belts 226 a and226 b. Each of the outer pulleys 222 a and 222 b is fixed relative tothe axle 215 onto which it is mounted. The first drive system furtherincludes a pair of counter-rotating gears 228 a, 228 b which are rotatedby first onboard motor 230 (FIG. 3B). So driven, belts 226 a and 226 bdrive pulleys 222 a and 222 b, respectively and this rotary motion ofthe pulleys 222 a and 222 b causes rotation of the geared wheels 200mounted on a corresponding shaft 215. Accordingly, when the vehicle 200is moving vertically, the geared wheels 220 carry the weight of thevehicle and any item(s) thereon.

In the embodiments of FIGS. 3A and 3B, the drive axles 215 are rotatablymounted within housing 232 such that their spacing remains fixedrelative to one another. As will be described shortly, the fixed spacingbetween axles 215 in accordance with some embodiments necessitates analignment step with the guiding system (e.g., tracks) before entry of avehicle into the columns which extend between the vertical arrays ofstorage areas 115 (FIG. 1C) and within which the guide system ismounted.

In alternate embodiments (not shown), elements of the first drivesystem, as geared wheels 200 and axles 215 may be mounted within housing232 in a manner that allows them to move inwardly so as to relax anyrequirement for precise alignment while also eliminating the risk of anydamage to either the geared wheels 200 or to the guiding system. Inembodiments of the latter type, vehicles intended to carry substantialloads may require motor driven means for temporarily reducing thespacing between axles 215 and thereby accommodate entry of a vehicle 200into the column(s) between storage areas.

With continued reference to FIGS. 3A and 3B, it will be seen that firstmotor 230 is operatively connected with the gears 228 a and 228 b todrive belts 226 a, 226 b and rotate both axles 215 and correspondinggeared wheels 220 in a synchronous manner. The first drive system forthe vehicle 200 is thus configured to synchronously drive the vehicle200 in a vertical direction relative to a track or other guiding system.Specifically, each geared wheel 200 is connected to an end of one of theaxles 215 in a manner that substantially impedes rotation of the gearsrelative to the axle. In this way each axle drives the attached twogears in a synchronous manner. Additionally, in the present instance,both axles are driven in a synchronous manner so that all four gears aredriven in a synchronous manner.

In embodiments, a single drive motor 230 is used to drive both axles. Inthis instance, pulleys 222 a and 222 b serve as timing pulleys rigidlyconnected to the axles 215 to prevent rotation of the pulley relative tothe axle. Similarly, timing pulleys (not shown) are connected to thecounter rotating gears 228 a and 228 b driven by motor 230. In thisinstance, drive belt 226 a connects the timing pulley 222 a with thetiming pulley directly driven, via gear 228 a, by motor 230, while thedrive belt 226 b connects the timing pulley 222 b with the timing pulleyindirectly driven, via gear 228 b, by motor 230. In embodiments, belts226 a and 226 b are each timing belts such that rotation of the drivemotor 230 is precisely linked to the rotation of the axle.

There are various other mechanisms that can be used to synchronouslydrive the axles 215 other than the single-motor arrangement exemplifiedby FIGS. 3A and 3B. For instance, a pair of drive motors can be used todrive the axles, and the drive motors can be synchronized. Inembodiments, the drive motor 230 includes a sensor that is operable todetect the rotation of the motor to thereby determine the distance thevehicle has traveled. Since the gears 200 are rigidly connected with theaxles, which are in turn synchronously connected with the drive motor230, the vertical distance that the vehicle moves can be exactlycontrolled to correlate to the distance that the drive motor 230 isdisplaced. For instance, the sensor 252 may be a sensor such as a hallsensor. The sensor detects the rotation of the motor and sends a signalto a central processor, which determines how far along the designatedpath the vehicle 200 has traveled based on the known informationregarding the path and the rotation that the sensor detects for themotor.

With reference now to FIGS. 2C, 3B, and 4A to 4G, there is shown anembodiment of vehicle 200 which further includes a clutch mechanism 400(FIGS. 4B and 4C) that can be engaged (FIG. 4C) and disengaged (FIG. 4B)to initiate and terminate transmission of power, respectively, from themotor(s) of the second drive system to the transfer mechanism, wherebythe second drive system may be operated independently of the transfermechanism. In this instance, the clutch mechanism 400 is configured astwo clutch sub-assemblies which are symmetrically arranged relative to alongitudinal centerline of vehicle 200, with these sub-assemblies beingindicated generally at 400 a and 400 b in FIGS. 2C and 3B. In FIGS. 4Band 4C, only first clutch sub-assembly 400 a is visible and includes afirst pivotable carrier 410. However, returning briefly to FIG. 3B, itwill be seen that second clutch sub-assembly 400 b is constructed in thesame fashion as sub-assembly 400 a and, as such, includes a secondpivotable carrier 412.

As best seen in FIG. 4B, each clutch sub-assembly as first clutchassembly 400 a includes a pivotable carrier, as first pivotable carrier410, that is maintained in a first angular orientation, relative to anunderlying support surface S while the full weight of vehicle 200 isdistributed among wheels 254 a, 254 b, 256 a, 256 b, 252 a and 252 b.Comparing FIG. 4C with FIG. 4B, it will be appreciated that as thevehicle 200 moves vertically in a direction away from underlying surfaceS, pivotable carriers 410 (and 412) are urged by a compressed coilspring 414 into the second angular position, which is reached whenvehicle 200 has reached an elevation above surface S that is of at leastdimension gi shown in FIG. 4C. Returning once again to FIG. 3B, it willbe seen that a first driven element 270 is rotatably coupled to thefirst pivotable carrier 410 and that a first endless loop element 274transfers rotary power to the first driven element 270. Likewise, asecond driven element (not shown) of the identically constructed secondclutch sub-assembly 400 b is rotatably coupled to the second pivotablecarrier 412, and a second endless loop element (not shown) transfersrotary power to the second driven element in the same manner asdescribed for the first clutch sub-assembly.

In this instance, each of the endless loop elements as endless loopelement 274 is a belt, it being understood that a chain mightalternatively be used without departing from the spirit and scope of thepresent disclosure.

With continued reference to FIGS. 4B and 4C it will be seen that eachclutch mechanism sub assembly, as sub-assembly 400 a of a vehicle 200constructed in accordance with one or more embodiments, additionallyincludes a first pulley 280. The first pulley 280 and first drivenelement 270 of sub-assembly 400 a are driven by the second motor ofvehicle 200. Likewise, although not shown, a second pulley and seconddriven element of sub-assembly 400 b are driven by the third motor ofvehicle 200. In this instance, the first pulley 280 and second pulleyare dimensioned and arranged to engage the first endless loop element274 and the second endless loop element, respectively, to drive thefirst and second driven elements whenever the corresponding drive motoris rotated. That is, regardless of whether clutch mechanismsub-assemblies 400 a and 400 b are engaged to drive the transfermechanism, the first and second driven elements will rotate as thesecond and third motors, respectively, are rotated.

As noted previously, and in accordance with one or more embodimentsconsistent with the present disclosure, the second and third motors arecoupled to engage the transfer mechanism only when the vehicle has beenelevated, relative to an underlying support surface S, by dimension H(FIG. 4C). Such elevation causes the pivotable carrier 410 to pivot outof the first angular orientation shown in FIG. 4B and into the secondangular orientation shown in FIG. 4C. In this instance, coupling of thesecond motor to the transfer mechanism is achieved, in clutch mechanismsubassembly 400 a, by a third driven element 272 which pivots intodriven engagement with first driven element 270. In like manner,although not shown, coupling of the third motor to the transfermechanism is achieved, in clutch mechanism sub-assembly 400 b, by afourth driven element 272 which pivots into driven engagement with thesecond driven element.

As shown in FIGS. 4A to 4C, rotation of the engaged third and fourthdriven elements—of which only fourth driven element 272 b is shown inFIG. 4C—causes rotation of first sprocket 290 a, 290 b which, in turncauses first and second chains 214 a, 214 b to move pin 212 a (FIG. 4A)and pin 212 b (FIG. 4B) toward or away from a container to betransferred to or from vehicle 200. When the wheels of vehicle 200 onceagain rest upon the surface S, as depicted in FIG. 4B, the third andfourth driven elements are again decoupled from the first and seconddriven elements, respectively. As such, continued operation of thesecond and third motors of the vehicles as to propel vehicle 200 uponsurface S, ceases to have any effect on the transfer mechanism 210.

In some applications, it may be desirable that vehicle 200 be capable ofloading and unloading other kinds of items than those configured astotes dimensioned and arranged to receive a plurality of inventoryitems. Such other kinds of items, by way of illustrative example, mayinclude boxes, cartons, trays and the like, or any combination of these,and they may contain one or a plurality of items of inventory. In one orembodiments, such items are accommodated by a transfer mechanism 210which incorporate an alternative or additional discharge assistant. Withparticular reference to FIGS. 2G and 4A to 4D, it will be seen thatrotation of sprocket 290 causes chains 214 a, 214 b to drive sprockets217, wherein each of the driven sprockets causes rotation of acorresponding one of the rollers, as rollers 211 (FIG. 2G). Thedirection in which the pairs of sprockets 217 are rotated determineswhether the rollers of transfer mechanism 210 are operated to assist inloading or in unloading of an item,

FIGS. 4D and 4E are side elevation views of the exemplary automatedguided vehicle 200 of FIGS. 2A-2F, the lateral exterior cover platebeing omitted to reveal an optional actuator mechanism 400 having aforce imparting member 402 which is selectively movable between a firstposition (FIG. 4D) and a second position (FIG. 4E). FIG. 4F is anenlarged view of the actuator mechanism 400 depicted in FIGS. 4D and 4E,the force imparting member 402 being shown in the first, non-forceimparting position. FIG. 4G is an enlarged view of the actuatormechanism depicted in FIGS. 4D to 4F, the force imparting 402 thereofbeing shown in the second, force imparting position.

As noted previously in the discussion of FIG. 4F, the wheels 220 aremounted onto two parallel spaced apart axles, as axle 215 depicted inFIG. 2F, so that two of the wheels are disposed along the forward edgeof the vehicle and two of the wheels are disposed along the rearwardedge of the vehicle. In one or more embodiments, the optional actuatormechanism 400 includes a threaded portion 404 of each axle 215 and arespective pair of carriers 406. Each respective carrier 406 has acorrespondingly threaded bore dimensioned and arranged to receive thethreaded portion 404 of an axle 215, and carries one of a pair of forceimparting members 402. In one or more embodiments, the force impartingmembers are rollers which are freely rotatable within carriers 406 aboutaxes of rotation which are transverse to the axes defined by axles 215.

To provide better steering control as can be obtained by differentiallydriving the forward or rearward pair of omnidirectional wheels, theinventors herein have determined that the force imparting members 402can be selectively actuated without the need for a dedicated motor. Inthis instance, rotation of motor 230 (FIG. 3B) causes axles 215 torotate, which brings carriers 406 forward until they encounter a stopwhereupon continuation of the axles 215 produces no further movement ofthe carriers 406. When positioned as shown in FIG. 4G, each forceimparting members exerts a normal force upon a surface of one of thewheels as, for example, while the wheels 252 a, 252 b are being drivenby the second and third motors, respectively. Such actuation of theforce imparting members 402 increases frictional contact of wheels 252 aand 252 b and thereby provides better directional control as the vehicle200 is moved across underlying surface S (FIG. 4G). As the wheels 252 a,252 b are only required while the vehicle is external to the array ofstorage area 215, motor 230 and axles 215 are able to serve a dualpurpose.

Thus, with continuing reference to FIGS. 3B and 4D to 4G, it will beseen that in some embodiments, vehicle 200 includes a first pair ofmotor driven omnidirectional rollers and a second pair of motor drivenomnidirectional rollers, wherein a first omnidirectional roller of eachpair is dimensioned and arranged to rotate about a first axis ofrotation, wherein a second omnidirectional roller of each pair is drivenfor rotation about a second axis of rotation, a fifth roller driven byone of the first motor and the second motor; and an actuator movablefrom a first position to a second position to selectively urge the fifthroller in a direction toward an underlying support surface; wherein asurface of each of the first and second pairs of omnidirectionalrollers, and a surface of the fifth roller are dimensioned and arrangedto contact the underlying support surface while the actuator ismaintained in the first position, and wherein movement of the actuatorinto the second position causes a transfer of load from one or more ofthe omnidirectional rollers to the fifth roller.

In one or more embodiments, the vehicle 200 may be powered by anexternal power supply, such as a contact along a continuous chargingrail or, alternatively, using an inductive power transfer coil, eitherof which serving to provide the electric power needed to drive thevehicle. However, in the present instance, the vehicle 200 includes anonboard power source that provides the requisite power for both thefirst drive motor 230 and the motors that drive the second drive system.In embodiments, the onboard power supply is rechargeable. In thatregard, the power supply may include a power source, such as arechargeable battery, a bank of ultra-capacitors, as capacitors 240(FIG. 3B) or a combination of these. For example, ultra-capacitors canaccept very high amperage in a recharging operation. By using a highcurrent, the ultra-capacitors can be recharged in a relatively veryshort period of time, measurable in seconds or minutes as compared tothe hours which may be required to charge a suitable battery. On theother hand, provisions can be made, according to one or moreembodiments, to automate the process of replacing a discharged battery,with a recharged one, as part of the process of operating one or more ofthe vehicles.

Where a charging rail is used, each vehicle 200 includes one or morecontacts for recharging the power source. In the present instance, thevehicle includes a plurality of brushes, such as copper brushes that arespring-loaded so that the brushes are biased outwardly. The brushescooperate with a charging rail to recharge the power source, asdescribed further below. For instance, a pair of charging rails (notshown) may be disposed along the columns within which the vehicles 200move during a sequence one or more storage and/or retrieval tasks.Alternatively, vertical and/or horizontal charging rails may be arrangedwithin charging stations (not shown) disposed in the vicinity of thedelivery station 120 (FIG. 1C).

In embodiments, the charging rails are conductive strips connected withan electrical supply. The charging contacts of the vehicle 200 engagethe conductive strips to recharge the ultra-capacitors. Specifically,the biasing element of the brushes biases the brushes outwardly towardthe charging contacts. The electricity flowing through the chargingcontact provides a high amperage, low voltage source that allows theultra-capacitors to recharge in an interval measurable in seconds orminutes, depending upon the amount of power consumed during a sequenceof inventory management tasks or subtasks.

Since the power supply provided by the ultra-capacitors may last foronly a few minutes, vehicles utilizing ultra-capacitors as a powersource may recharge charges each time the vehicles travel within aloading column and/or utilize a charging station disposed along a pathtaken in the course of performing inventory management tasks requiringan association with one or more FAMs, as FAMs 18 (FIGS. 1A and 1B) orFAMs 40 and 50 (FIGS. 1B and 10 ).

In one or more embodiments, each vehicle may include a load sensor fordetecting that an item is loaded onto the vehicle. The sensor(s) ensurethat the item is properly positioned on the vehicle. For instance, theload sensor may include a force detector detecting a weight change or aninfrared sensor detecting the presence of an item.

In the embodiments of FIGS. 1A to 1C, the automated guided vehicle orAGV may be sei-autonomous or, alternatively, fully autonomous. In thelatter regard, a multitude of non-contact systems have been proposed forthe purpose of continuously determining the actual position of anautomated guided vehicle in absolute coordinates, and resettingnavigational parameters (i.e., X, Y, and heading) to null outaccumulated errors, thereby re-referencing the vehicle. Any of these maybe utilized in the implementation of position referencing for automatedguided vehicles in an inventory management system consistent withembodiments of the present disclosure. Such referencing systems can beultrasonic, RF, or optical in nature, with ultrasonic and optical beingespecially suited to indoor scenarios. Of these latter two categories,optical systems are generally more accurate and therefore more widelyemployed in commercial practice.

Exemplary position sensing systems utilize a scanning mechanism thatoperates in conjunction with fixed-location references strategicallyplaced at pre-defined surveyed sites. Such scanning mechanisms mayinclude scanning detectors with fixed active-beacon emitters, scanningemitter/detectors with passive retroreflective targets, scanningemitter/detectors with active transponder targets, and rotating emitterswith fixed detector targets.

In one or more illustrative embodiments consistent with the presentdisclosure, automated guided vehicles rely on a scanning lasertriangulation scheme (SLTS) to provide positional updates to an onboarddead-reckoning system of the vehicle. A laser emitter rotating at, forexample, two rpm illuminates passive retroreflective barcode targetsaffixed to walls or support columns at known locations one the order offifteen meters away from the vehicle. The barcodes are used topositively identify the reference target and eliminate ambiguities dueto false returns from other specular surfaces within the operating area.An onboard computer of each vehicle calculates X-Y positional updatesthrough simple triangulation to null out accumulated dead-reckoningerrors.

By way of additional example, each automated guided vehicle 200 mayutilize retroreflective targets, distributed throughout the operatingarea, in a manner which allows both range and angular orientation to bedetermined by each vehicle. In an embodiment, a servo-controlledrotating mirror on the AGV pans a near-infrared laser beam through ahorizontal arc of 90 degrees at, for example, a 20-Hz update rate. Whenthe beam sweeps across a target of known dimensions, a return signal offinite duration is sensed by the detector. Where the retroreflectivetargets are all the same size, the signal generated by a close targetwill be of longer duration than that from a distant one. Anglemeasurement is initiated when the scanner begins its sweep from right toleft, where detection of the reflected signal terminates the timingsequence.

As yet another position reference technique which may be employed in anautomated guided vehicle consistent with the present disclosure is alaser-based scanning beacon system computes vehicle position and headingusing cooperative electronic transponders with passive reflectors. Sucha scanner mechanism includes a rotating mirror attached at, for example,a 45-degree angle to the vertical shaft of an incremental opticalencoder. In order to achieve increased azimuthal accuracy, a timerinterpolates between encoder counts. The fan-shaped beam is divergesvertically at, for example, a four degree spread angle, to ensure targetdetection at long range while traversing irregular floor surfaces. Eachtarget is uniquely coded, and many (e.g., 32) targets can be processedin a single Scan, with vehicle X-Y position calculated every 100milliseconds.

In one or more autonomous embodiments, each AGV maintains, in memory, aninternally stored map of its own position within a facility. Inaddition, each AGV reports its position, speed, angular orientation inthe plane of travel, and a selected path of travel data to othervehicles in the facility, and the AGV receives such data from othervehicles. Using the AGV data, each vehicle maintains a dynamicallyupdated map which reflects the position of all vehicles in theparticular zone(s) of an inventory management facility to which thatvehicle has been assigned. When dynamically updated position data isavailable locally at each vehicle, a task may be assigned to a vehicleby a central controller as controller 450, in embodiments, the pathsegments taken by a vehicle to reach the location(s) where elements ofthe assigned task are to be performed may be selected by the vehicle.

In an embodiment, each vehicle is configured to execute, by a processorlocal to that vehicle, steps of a navigation process stored in memorywhich cause the vehicle to follow a shortest path from a currentlocation of the vehicle to a destination where the next subtask(s) of anassigned task are to be performed. In such embodiments, the centralcontroller 450 need not be configured to execute traffic control andcollision avoidance functions (unless a backup control scheme isdesired) but, instead, central controller 450 may be configured totransmit signals representative of instructions which identify the nexttask(s) to be assigned to each vehicle and which specify the variouslocations within the facility where those tasks are to be performed. Thevehicles, on the other hand, may be configured to transmit signals tothe controller which are representative of task assignmentacknowledgements, position updates, status updates (e.g., sub-taskcompleted or in process, current power status, etc.), and otherinformation which the controller may require to assess the relativeability of the vehicles to perform tasks awaiting assignment.

In a fully autonomous scheme according to one or more embodiments, eachvehicle may alternatively utilize a local processor to determine speedand direction of movement from sensed indicia placed on an underlyingsupport surface in one or more zones of an inventory managementfacility, to exchange that positional data with other vehicles withinthe facility, and to maintain a dynamically updated, local map toachieve a form of decentralized traffic control in manner similar tothat described above using other positional sensing approaches.

In semi-autonomous configurations of AGVs consistent with the presentdisclosure, a central controller, as controller 450, provides trafficcontrol functions needed, for example, to prevent collisions of thevehicles with one another and/or with any potential obstructions tovehicle movement which may be present in the one or more zone(s) of afacility to which a subset of vehicles are assigned. In suchembodiments, controller 450 receives current position and bearing datain the form of update signals transmitted from the vehicles 200. Inembodiments, the received position and bearing data is compared withestimates that the controller has derived from prior speed and headinginstructions transmitted by the controller to the vehicle. Based on thecomparison, the controller 450 may determine that corrections to one ormore of the speed and direction of one or more vehicles is needed toprevent a collision and, if so, transmit those instructions to thevehicle(s).

In one or more semi-autonomous embodiments consistent with the presentdisclosure, each vehicle 200 may include a reader for reading indiciaplaced on a surface upon which the vehicle is traveling and/or inpositions within access columns aligned with the array of storage areas115 (FIG. 1C). In some embodiments, each indicium of a first group ofindicia corresponds to a unique location to form a grid of locations.These locations may be stored in a data table in a memory accessible toa processor of the vehicle, of the central controller 450, or a both. Byfollowing a path designed to intersect with a particular sequence ofthese indicia, each vehicle may transmit an identifier of an indicium asit passes over it and confirm it to controller 450 whereupon asemi-autonomous guiding of the vehicle is achieved via instructionstransmitted by the controller to the vehicle. From this information andother data reported by each vehicle, controller 450 can confirm thespeed, direction, and path of movement for each vehicle. In one or moreembodiments, controller 450 utilizes speed and directional data toenforce collision avoidance policies, to assign inventory managementtasks according to the location and power reserve status of each vehicleand, in the interest of safety, to maintain an appropriate distance fromany personnel permitted in the area.

Additional indicia may be affixed, within the access columns or tostored totes themselves, at positions adjacent to each of storagelocations 115 (FIG. 1C). Here, each indicium may bear include a uniquebar code, and the reader on each vehicle 200 may scan the area aroundthe storage location 115 at which an item is to be delivered orretrieved. The data that the central processor 450 has regarding thepath that a vehicle 200 has to follow and the data regarding thedistance the vehicle has traveled based on the data regarding therotation of the drive motor may be sufficient to determine whether thevehicle 200 is positioned at the appropriate storage location within thestorage areas 115. Nonetheless, indicia adjacent the storage areaspermits a redundancy check of the location of the vehicle before an itemis discharged into or received from the appropriate storage location.Therefore, the scanner may operate to scan and read informationregarding the storage location at which the vehicle is stopped. If thescanned data indicates that the storage location is the appropriatestorage location, then the vehicle discharges its item into the storagelocation. Similarly, the vehicle may have a second reader for readingindicia adjacent the rearward edge of the vehicle. The second reader maybe used in applications in which the system is set up to utilize a firstseries of storage locations along the forward side of an access columnand a second series of storage locations along the rearward side of anaccess column, as shown in FIG. 1C.

In some embodiments, functionality for autonomous or semi-autonomousguidance of the vehicles 200 may be integrated into one or more of theFAMs, as for example, FAMs 18 of FIG. 1A. Such an approach may bebeneficial where precise position sensing is required in some zoneswithin an inventory management facility, but a less precise positionsensing approach may be acceptable in other zones. For example, inembodiments such as that depicted in FIG. 1A, FAMs 18 are depicted asserving a supporting role to warehouse workers and thus may be requiredto maintain a safe distance but nonetheless remain in proximity to carryout the supporting task(s). It suffices to say, from the foregoingdiscussion of various non-limiting examples, that a variety oftechniques and systems may be employed in order to coordinate thepositions of AGVs and associated FAMs in an inventory management system.

In the foregoing description, the vehicles have drive gears 220 that aredimensioned and arranged to interact with teeth of respective, inwardlyfacing tracks disposed within each access columns. Such interaction caneffect raising or lowering of a vehicle, depending upon the direct ofrotation of motor 230. As well, one or more of the FAMs may incorporatetracks having teeth so as to permit a vehicle to raise and lower a FAMwith which it is associated along with one or more of the structureswith which a FAM is docked, as FAM 18 or FAM 50. In addition, the teethof drive gears 220 may alternatively be actuated to actuate mechanismswhich are part of a FAM. As will be explained later, for heavier loads(e.g., on the order of 300 kg or more), multi-shelf FAMs 40 such asthose depicted in FIGS. 1B and 1C, may be equipped with an internal,gear driven jack mechanism actuated by rotation of the gears 220 so asto minimize the amount of torque needed by motor 230 to initiate andmaintain elevation of FAMs 40 during their movement upon an underlyingsurface.

In some embodiments, the processor of each vehicle controls theoperation of the vehicle in response to signals received from thecentral processor 450. Additionally, the vehicle includes a wirelesstransceiver so that the vehicle can continuously communicate with thecentral processor as it travels along the track. Alternatively, in someapplications, it may be desirable to incorporate a plurality of sensorsor indicators along paths which the vehicles may traverse. The vehiclemay include a reader for sensing the sensor signals and/or theindicators, as well as a central processor for controlling the operationof the vehicle in response to the sensors or indicators.

FIG. 5A is a front perspective view depicting the use of an automatedguided vehicle 512 in conjunction with a functional accessory module(FAM) 518 of a first group of functional accessory modules, according toone or more embodiments. FIG. 5B is a perspective view depictingpre-docking alignment of the automated guided vehicle 512 of FIG. 5A,with a first illustrative base 514 which may be realized either as anintegral part of a functional accessory module, as any of the functionalaccessory modules shown in FIGS. 1A to 1C and 5A, or as a separatefunctional accessory module serving as an adaptor between the vehicleand at least one of those other types of functional modules, accordingto respective embodiments. Where FAM 518 is expected to accommodateheavy loads, base 514 may incorporate an internal jack mechanismactuated by gears, as gear 515, dimensioned and arranged with the gearwheels 520 of vehicle 512.

FIG. 5C is a perspective view depicting post-docking alignment of anautomated guided vehicle 512 with a second alternative base 516 whichmay be realized either as an integral part of a functional accessorymodule, as any of the functional accessory modules shown in FIGS. 1A to1C and 5A, or as a separate functional accessory module serving as anadaptor between the vehicle and at least one of those other types offunctional modules, according to respective embodiments.

FIG. 5D is a rear elevation view of an automated guided vehicle 512docked with a base 522 such as depicted in FIG. 5C or 5D, whererespective surfaces of each of the base and vehicle are in contact, atmultiple points 524 a, with underlying support surface S. FIG. 5E is arear elevation view of the docked automated guided vehicle 512 of FIG.5D, after the first drive system of the vehicle, which comprises frontand back pairs of geared wheels, as wheels 526 a and 526 b, has beenactuated by rotation of gear wheels 520 in the direction of the arrows,to lift the base with which it is docked, such that none of the surfacesof the base, including surface regions 524 a and 524 d, are in contactwith the underlying support surface S. In this instance, base 514incorporates an internal jack mechanism that includes linearlyextendable legs 528 a and 528 b which are downwardly displaced as gearwheels 520 are rotated to drive one or more gears of the drivemechanism, as gear 515.

FIG. 6A is a perspective view depicting post-docking alignment of anautomated guided vehicle 612 with a third alternative base 614 which maybe realized either as an integral part of a functional accessory module(FAM) as one or more of the FAMs shown in FIGS. 1A to 1C and 5A, or asan auxiliary (FAM) dimensioned and configured to serve as an adaptorbetween the vehicle and at least one or more of those other types FAMs,according to respective embodiments. In this instance, base 614 is anauxiliary FAM dimensioned and arranged to permit vehicle 612 to enter,lift, and transport FAM 618 (FIG. 6C).

To accommodate entry of vehicle 612, the base 614 of the auxiliaryadaptor defines a central entry opening with lateral recesses, indicatedgenerally at 615 a and 615 b. As best seen in FIG. 6B, which is a rearelevation view of the docked automated guided vehicle 612 of FIG. 6A,each of the lateral recesses 615 a and 615 b is aligned with acorresponding segment of track, as track segment 616 a and 616 b,respectively. The track segments 616 a and 616 b are affixed to interiorsurfaces of base 614 and aligned with each other such that both arevertically oriented while the bottom surface 617 of the auxiliaryadapter is resting upon a substantially horizontal underlying supportsurface.

Vehicle 612 may utilize gear wheels and axles which are drawn closertogether by an appropriate mechanism (not shown) to accommodate dockingwith any of the one or more FAM structures which have been and/or willbe described herein. In other embodiments consistent with the presentdisclosure, the distance between gear wheels 620 a and 620 b remainsfixed during the performance of all inventory management tasks—inclusiveof all phases of the vehicle alignment, FAM entry and FAM dockingprocedures. In such embodiments, precise alignment must be maintainedbetween the geared wheels of the vehicle 612, on the one hand, and thetrack segments, as segments 615 a and 615 b of the vehicle base, on theother hand.

To this end, one or more FAM embodiments may incorporate defeasibleinterlock structures such, by way of illustrative example, asprotuberances (not shown). For example, the auxiliary FAM of FIGS. 6Aand 6B may include protuberances which extend downwardly from the bottomsurface of 217, with one or more drive systems of the vehicle 612 beingactuated to lower and lift the protuberances into and out of dimensioneddepressions formed, as by drilling, into the underlying support surfaceS. Such an arrangement might alternatively be reversed such that therecesses are defined in bottom surface 617 and the protuberances areaffixed, secured or otherwise formed so as to project upwardly from theunderlying support surface S.

A defeasible engagement between protuberances and depressions asdescribed above is one way to maintain the position of base 614 againstundesirable lateral shifting movements which might otherwise occur, forexample, during deceleration of the vehicle and FAM(s), from theapplication of unexpected impact forces during the docking procedure.Improper alignment between the gear wheels of vehicle 612 and the FAMduring docking is one source of potential impact. In that regard,sensors of the vehicle 612 might be employed to initiate a re-alignmentprocedure by which the vehicle 612 might back up, make a small angularadjustment and attempt re-entry into base 614. In one or moreembodiments consistent with the present disclosure, however, vehiclesconsistent with the present disclosure are configured to utilize analignment system, to facilitate proper registration of gear wheels of avehicle, as gear wheel 620 a-620 c of vehicle 612, and those FAMstructures utilizing track segments, as base 614.

Use of an alignment system minimizes the possibility of damaging eitherof the two structures (gear wheels and track segments) during thedocking procedure. In the embodiment of FIGS. 6A and 6B, the alignmentsystem comprises parallel, floor mounted guide rails, as rails 632 and634. Rails 632 and 634 are spaced apart by a gap dimensioned to receiveand guide the linear translation of one or more supports dependingdownwardly from vehicle 612. That is, rails 632 and 634 are separatedalong their length by a gap of sufficient width to accommodate entry andpassage of a series of guides, indicated generally at 633. Each guidedepends from the undercarriage of vehicle 612 by a rod indicatedgenerally at 635 (FIG. 6B).

Turning briefly to FIGS. 2C to 2F, it will be seen that the vehicle 200also incorporates a series of guides, indicated at 233. In FIG. 2C itcan be seen that these guides are arranged along a longitudinal centerline L. In embodiments, the guides 233 are arranged along the undersideof vehicle 612 in the same manner as that shown for guides 233 in FIG.2C. With when all guides 633 have entered the gap between rails 632 and635, proper alignment between vehicle 612 and base 614 (or any other ofthe FAM and storage structures depicted throughout the presentdisclosure) can be maintained. In the former regard, it should be notedthat the gap between rails 632 and 634 may taper from a larger widthdimension (at the point of lead guide entry) to a smaller widthdimension in order, for example, to relax the burden upon vehicle 612 toinitiate docking with the same tight dimensional tolerance as would berequired upon the point of entry at the base 614 of the auxiliaryadaptor FAM itself. In some embodiments, the taper may be monotonic inan entry transition zone. That is, the gap may be decrease in width at aconstant rate in the direction of vehicle movement toward a FAM withwhich it is docking, and thereafter the gap between rails may maintain aconstant width selected to maintain adequately precise alignment of thevehicle with its point of entry into the FAM. Where the vehicle isequipped with gear wheels, as vehicles 212 and 612, such alignment willbe determined by the spacing of corresponding teeth of the FAM guide orjack system with which the gear wheels will interact.

Once vehicle 612 maneuvers into a position of proper alignment with base614, one or more drive systems of vehicle 612 are operated such that itswheels, including omnidirectional wheels 654 a (FIG. 6A) and 656 a and656 b (FIG. 6B) cause the vehicle 612 to enter base 614._In embodiments,a motor (not shown) of the first drive system of the vehicle causesrotation of gear wheels 620 a and 620 b in the direction of the arrowsshown. Rotation of the gear wheels against the teeth of the racksegments, as rack segments 616 a and 616 b, causes the base 614 to beurged upwardly in the direction of arrow F. Once the vehicle 612 haslifted the base 614 with which it is docked, the bottom surface 617 ofbase 614 is no longer in contact with the underlying support surface S.

FIG. 6C is a perspective view of an inventory management system 600,depicting the placement and use of a plurality of functional accessorymodules 618 constructed in accordance with any of the embodiments shownin FIGS. 5A to 6B. In this case, vehicles 612 are shown disposed withinbases which are formed as an integral part of each FAM 618. Each FAM 618includes a plurality of bins, as bins 618 a and 618 b, which are mountedalong a stalk 619 so as to be at the right height above the underlyingground surface for a human operator H to remove items from the nearbystorage racks and place them into one of the bin. Thereafter, theoperator H may confirm conclusion of the completion of the transactionby entering data via a touch screens terminal, as touchscreen terminal621. In this instance, a second operator O located at a pickingdestination, removes items from bin 618 c or 618 d, and places them in acarton C for shipment.

With reference now to FIGS. 7A to 7D, it will be seen that FIG. 7A is aperspective view depicting pre-docking alignment of an automated guidedvehicle 712 with a first functional accessory module (FAM) 714 in theform of an auxiliary adaptor FAM between the vehicle 712 and at leastone or more of the other types of functional modules shown in FIGS. 1Ato 1C, according to respective embodiments. As in the above-describedexemplary embodiment of FIG. 6A and FIG. 6B, the embodiment of FIGS. 7Aand 7B may utilize a defeasible interlock system and alignment systemneither of which are shown) to facilitate the docking which must takeplace between vehicle 712 and auxiliary FAM 714. In furtherance of afunction to auxiliary FAM 714, namely the lifting of one or moredynamically deployable FAM structures (as FAM 718 of FIGS. 8A to 8C),the upper surface of FAM 714 may also include a plurality of upwardlyextending docking projections, indicated generally at 715. Inembodiments, projections 715 are dimensioned and arranged forregistration with corresponding structure as recesses 723 of auxiliaryFAM structure 718 of FIGS. 8A to 8C, during a docking procedure. Whendocked, projections 715 of FAM 714 form part of a defeasible interlockwith any auxiliary FAM structure while both are being transported acrossunderling support surface S by vehicle 712.

FIG. 7B is a perspective view depicting post-docking alignment betweenthe semi-autonomous vehicle 712 and the functional accessory module 714of FIG. 7A. FIG. 7C is a rear elevation view of the docked automatedguided vehicle 712 and first functional accessory module 714 of FIG. 7B,where respective surfaces of each of the vehicle and the firstfunctional accessory module are in contact, at points 724 a, 724 b, 724c and 724 d, with an underlying support surface S. FIG. 7D is a rearelevation view of the docked automated guided vehicle 712 and firstfunctional accessory module 714 of FIG. 7B, after a first drive systemof the vehicle comprising geared wheels 720 a and 720 b has beenactuated to lift the first functional accessory module, such that noneof the surfaces of the first functional accessory module 714, includingsurfaces 724 a and 724 d, are in contact with the underlying supportsurface.

With reference now to FIGS. 8A to 8C, it will be seen that FIG. 8A is apartial elevation view depicting pre-docking alignment of the dockedguided automated vehicle 712 and first or auxiliary functional accessorymodule (FAM) 714 of FIG. 7D with a second functional accessory module(FAM) 718, the second FAM being realized in this exemplary embodiment asa multi-level storage rack having storage shelves 719. The shelves 719of FAM 718 define corresponding storage surfaces 719 a which accommodateitems such as containers C of inventory articles, as shown in FIGS. 8Aand 8B, and/or individually boxed inventory items placed directly onsurfaces 719 a, as shown in FIG. 8C. FAM 718 also defines floor contactsurfaces 724 e and 724 f, which are dimensioned and arranged to supportthe rack upon the underlying support surface in accordance with one ormore embodiments.

FIG. 8B is a partial elevation view depicting post-docking alignment ofthe docked vehicle 712 and first or auxiliary FAM 714 of FIGS. 7D and 8Awith the second FAM 718, after a first drive system of the vehiclecomprising gear wheels 720 a and 720 b has been actuated to further liftthe first FAM 714 and also to lift the second FAM 718, such that none ofthe surfaces of the first or second FAMs are in contact with theunderlying support surface S. FIG. 8C is a full elevation view depictingrelative positions of the docked guided automated vehicle, first FAM714, and second FAM 718 following lifting of second FAM 718 andtransferring to another location in the manner shown in FIG. 8B.

FAMs as FAM 718 may be required to support and store a collection ofheavy items, as shown in FIG. 8C, with the total weight of the FAM 718and items stored thereon approaching 400 kg or even more. The inventorsherein have determined that an extra contact force supplied to thenon-omnidirectional drive elements can improve the maneuverability of avehicle transporting a heavily loaded FAM. Returning briefly to FIGS. 4Dto 4G, it will be recalled that vehicles consistent with the presentdisclosure, as vehicle 200 or vehicle 712, optionally include forceimparting members 402. The force imparting members 402 are selectivelymovable from a first or initial position (FIG. 4D), at which no force isapplied by a respective force imparting member 402 to a correspondingdrive element of vehicle 200 or 712. From their initial positions, theforce imparting members 402 are actuated into a second position (FIG.4E). In embodiments, the force imparting members 402 are rollers whichare freely rotatable within carriers 406 about a respective axis ofrotation. When moved into their respective second positions, as shown inFIGS. 4E and 4G, each roller 402 imparts a normal force against thesurface of the drive element over which it is positioned. Theapplication of this normal force, in turn, increases the frictionalcontact between the drive elements and the underlying support surface.

As best seen in FIG. 4E, enough of a force F_(N) may be imparted as tolift one or more of the omnidirectional wheels so as to create a gapg_(w) between each wheel and the underlying support surface S. Inpractice, the gap g_(w) will fluctuate and be different for each of theomnidirectional wheels at any given instant while the vehicle 200 istransporting a FAM 718. That is, the appearance in FIG. 4E of an equalgap g_(w) between forward and rear omnidirectional wheels, as to suggesta perfectly balanced load, is merely a transitory condition.

It suffices to say that vehicle 712 need not include force impartingmembers 402 or similar structure to enhance frictional contact with theunderlying support surface, particularly where FAMs carrying many orheavy items, as FAMs 718, will not be utilized in the performance ofinventory management tasks. By way of illustrative example, anarrangement such as that depicted in FIG. 1C may omit the FAMs 718entirely. In the present instance, however, vehicle 712 includes theforce imparting members 402 and a first onboard motor is used toindependently rotate one of the central drive elements, as drive element752 b, while a second onboard motor is used to independently rotate theother of the central drive elements. Turning in either direction, insuch an embodiment, is achieved by rotating the central drive elementsin opposite directions or, for a larger turn radius, both in the samedirection but one faster than the other. In addition, theomnidirectional wheels on one side, as wheels 754 b and 756 b may bedriven by the same onboard motor(s) being used to drive the centraldrive element on that side. By way of further example, a single, thirdonboard motor may be used to drive all of the omnidirectional wheels, asdescribed previously in connection with vehicle 200. In any of theforegoing example, and others, the transfer mechanism may be driven byyet another onboard motor, obviating the need for a clutch mechanism.

FIG. 9 is a partial perspective view depicting elements of an inventorymanagement system 900 that includes respective groups of first FAMmodules 714 and second FAM modules 718 with which automated guidedvehicles 712 are adapted to cooperate to perform corresponding subsetsof inventory management tasks, and also a group of third FAMs 918 withwhich vehicles 712 are adapted to cooperate to perform yet anothersubset of inventory management tasks, according to one or moreembodiments. Specifically, and in a manner to be described shortly byreference to FIGS. 10A and 10B, the vehicles 712 are further dimensionedand arranged to enter, lift, transport, and move vertically within atask completion zone Z circumscribed by adjacent pairs of columns 929 aand 929 b of FAMs 918.

Within the task completion zone Z, vehicle 712 is configurable, byoperation of the drive systems thereof, to cooperate with the guidesystem of FAM 918 and thereby elevate for transfer, individual inventoryitems or, in the alternative, containers, cases, cartons, and/or palletsof supporting multiple items of inventory. By operation of the transfermechanism, as for example, individually drive rollers as rollers 711 ofvehicle 712, such item(s) are transferred to a storage area of amulti-level flow rack structure 920 positioned adjacent to a destinationarea which includes pick stations PS. In the present instance, and asseen in FIG. 10B, the guide system comprises track segments 926 whichare secured or affixed to, or otherwise formed on the inwardly facingsurfaces of the columns 929 a and 929 b.

At a location proximate a pick station PS, one or more flow rackstructures as rack structure 920 can supply the pick station operator(s)with those items of inventory which are required, or expected to berequired based on a demand forecast, to fulfill inventory managementrequests in an upcoming inventory management interval (e.g., to satisfye-commerce or mail orders during one or more upcoming picking cycles).Such rack structures may be served by dynamically movable (anddetachable) FAMs 918 as depicted in FIGS. 9 and 10A to 10F. In addition,or by way of alternative, the FAMs 918 may be permanently attached tothe rack structure(s) 920 so that the vehicles as vehicles 712 mayutilize an already present FAM to accomplish an assigned inventorymanagement task such, for example, as transfer of an item to a deliveryzone of rack structure 920.

When not otherwise required for other inventory management tasks, orduring times where rack structure 920 is being replenished at a highrate, a subset of the total number of vehicles 712 deployed at a givenfacility may be reserved for use in one or more of the task activityzones Z of corresponding FAMs 918. Replenishment of items to the storagezone of the rack structure 920, during such times, may be achieved byactuating the transfer mechanism (e.g., rollers 711) of an arrivingvehicle 718 to shift the item from the arriving vehicle to the vehicle718 already disposed within the task activity zone of a FAM 918.Coordination of movements between the arriving and “local” transfervehicles may be through peer-to-peer communication among the vehicles,or it may be directed by a central controller.

Vehicles and FAMs configured in a manner consistent with the presentdisclosure may be used with a variety of flow rack structures 920. Someflow rack structures may feed articles to the pick stations PS usingunpowered rollers for single direction feeding assisted solely by theforce of gravity. Alternatively, and as shown in FIG. 9 , rack structure920 may utilize a bidirectional network of parallel belts 932 or otherconveying element(s) in order advance items toward or away from the pickstations PS. In such an embodiment, feeding of articles transferred byone of vehicles 718 to a pick station requires driving one or more ofbelts 932 in a first direction away from the vehicle and toward the pickstation(s).

Conversely, removal of items from rack structure 920 requires a reversalof the aforementioned vehicle-to-rack-structure process. Such a reversalmay be warranted, for example, when a different subset of articles areto be stored in rack structure 920 as preparation for a new item pickingcycle. In addition or alternatively, items currently stored on thesurface of belts 920 may no longer be required during the current andapproaching pick cycles at the same picking volume as they werepreviously. In that regard, a reallocation of items—between areasreserved for fast moving inventory items as exemplified by the placementof flow rack structure 920 in FIG. 9 —and those remote areas bettersuited for slower moving inventory items, may be advantageous in orderto maintain an acceptably low average travel time per picker. Forexample, during non-peak times, when fewer agents are available toretrieve items for picking from remote storage areas, greater efficiencycan be achieved by temporarily bringing some slower moving items intothe rack structure 920 via vehicles 718. Such action provides agentswith access to these items during one or more non-peak inventorymanagement interval. In preparation for a subsequent interval where, forexample, more pick and place agents are available, the slower movingitems are moved back into a remote storage zone.

In one or more embodiments, vehicles 718 incorporate a dischargeassistant (not shown) which is operated in coordination with thetransfer mechanism of a vehicle so as to align an item being transferredfrom the vehicle to a target area of rack structure 920. To transfer anitem from one of the vehicles 718 to a specific subset of belts 932 offlow rack structure 920, the controller of the vehicle is configured tooperate the discharge assistant so as to urge the item to be transferredin a direction transverse to the direction in which the transfermechanism of the vehicle advances that item toward that subset of belts932, thereby establishing and maintaining the requisite alignment. As anillustrative example, the discharge assistant comprises a pusher bar(not shown) dimensioned and arranged to project from one of the twosidewalls of the vehicle 718, above the support plane defined by theuppermost surfaces of rollers 711.

As an extension of the dynamic inventory allocation utilizing vehiclesand FAMs consistent with the present disclosure, and with continuingreference to FIG. 9 , it will be appreciated that other inventory itemsmay be stored on the shelves of that first subset of FAMs 718, indicatedat 718 a, which is closest to the picking station. Items which are lessfrequently needed than those stored in FAMs 718 a and/or flow rackstructure 920, but for which access will be needed at some point duringthe current or an approaching inventory management cycle, may be storedin a second subset of FAMs 718, indicated at 718 b, which are somewhatmore remote from the picking stations PS. Still other subsets of FAMs718 (not shown), used for the storage of items not needed during acurrent or an approaching inventory management cycle, may be locatedstill further away than FAM subsets 918 a and 918 b.

Also shown in FIG. 9 is an additional vehicle 712 carrying a containerC1 directly away from a pick station operator after its contents havebeen removed and transferred to one of the shipping cartons C2 beingmoved by outfeed conveyors 922 and 924, respectively. In someembodiments, cartons C1 are lifted by vehicle 712 after maneuvering intopositions underneath the work surfaces WS which are in front of theoperators. To that end, aligned, inwardly facing track segments (notshown) are provided for the vehicles to enter and move upwardly, byrotation of the gear wheels in a first direction which brings thecartons C1 into the positions shown in front of the operators. Once thedesired quantity of item(s) has been removed from a carton C1, the gearwheels of a vehicle are operated in the reverse direction, lowering thevehicle so that it can be deployed for the next scheduled inventorymanagement task that has been assigned to it.

It suffices to say that using vehicles and FAMs configured in accordancewith embodiments of the present disclosure enables a diverse pluralityof inventory storage modalities, and the inventory therein, to bedynamically employed and repositioned over the course of each inventorymanagement window. This is true whether the window extends across anentire inventory management cycle (which may be from six hours to entire24 hour day inclusive of picking and replenishment operations) orwhether the window is subdivided into multiple intervals so as to bettermatch fluctuations in both demand for specific inventory items andavailability of manpower resources to process them. As well, those samevehicles may retrieve and return items to statically positioned storageareas, further enhancing the efficiency of a warehouse facility over thecourse of an inventory management cycle.

FIGS. 10A and 10B are elevation views depicting docked alignment betweenan automated guided vehicle 712 and one of the FAMs 918, but prior toactivation of the first drive system which in the illustrativeembodiment of FIGS. 10A and 10B comprises gear wheels 720 a and 720 baccording to some embodiments. To maintain the FAM 918 in a position ofregistration with a flow rack structure as, for example, depicted FIG. 9, and as best seen in FIG. 10B, one or more embodiments of FAM 918include(s) upper and lower docking clips, indicated generally at 927 aand 927 b, respectively. When FAM 918 has been aligned with a rackstructure, it is lowered into position by vehicle 712, which brings thedocking clips into engagement with corresponding clips secured to orotherwise formed on the flow rack structure.

FIG. 10C is an enlarged, partial elevation view taken from theperspective of FIG. 10A and depicting facing alignment of a rotaryelement as gear wheel 720 b of the first drive system with acorresponding portion of the guide system of FAM 918. In the instantcase, the guide system of functional accessory module 918 comprisesinwardly facing tracks as tracks 926. Once vehicle 712 has entered theinterior space defined between the vertical columns 929 of FAM 918, thegear wheels of the vehicle are rotated such that the drive system wheelsengage with the guide system of FAM 918 which, in the present instance,comprise inwardly facing pairs of tracks 926 which engage with gearwheels 720 a and 720 b. Rotated one way, the FAM 918 is lifted above theunderlying support surface and the FAM can be transported by the vehicle712. Once in a position of alignment, the gear wheels of vehicle 712 arerotated in the opposite direction to lower FAM 918 such back onto theunderlying support surface. In the process, the aforementioned dockingclips 927 a and 927 b are engaged. Lifting of the FAM 918 by vehicle 712for transport is depicted in FIG. 10C to FIG. 10E.

As will be appreciated by reference to FIGS. 10A and 10B, the procedureby which a vehicle consistent with the present disclosure, as vehicle712, aligns with and enters a FAM as FAM 918 can be performed withoutregard to whether a FAM 918 is already engaged in the transport of anitem to a destination area. Indeed, an advantageous feature of someembodiments consistent with the present disclosure is that each vehicleis configured to complete some or all assigned inventory managementtasks without the use of an accessory module, such as the retrieval ofan item C from a storage area 110 of a vertical array of such storageareas as depicted in FIG. 1C, the transfer of an item C from one storagearea 110 to a different storage area 110, the delivery of an item ascontainer C to a picking station, or any combination of these, accordingto a first mode of operation. In embodiments such as those depicted inFIGS. 9 and 10A-12 , the same vehicle is also configured to completeother tasks by acquiring and utilizing a single or multiple FAMs inorder to complete one or more additional inventory management tasks,according to a second mode of operation. FIGS. 10C to 10E, for example,illustrate a vehicle 712 configured according to a second mode ofoperation to enter FAM 918, to lift that FAM while carrying a container,to horizontally displace the FAM 918 to a different location, and tolower that FAM at the different location. As shown in FIG. 10F, vehicle712 is further configured to climb within the FAM 918 in furtherance ofan inventory management task.

FIG. 10D is an enlarged partial elevation view taken from the sameperspective as FIGS. 10A and 10C, but after actuation, in a firstdirection, of respective rotary drive elements, as gear wheels 720 a and720 b of the first drive system of the vehicle 712 with correspondingfacing track portions 926 of the guide system of the functionalaccessory module 918, which serves to lift FAM module 918 above thesurface in the manner shown in FIG. 10D, according to one or moreembodiments. FIG. 10E is an elevation view taken from the sameperspective as FIG. 10B, but after actuation, in the first direction, ofthe rotary elements of the first drive system with corresponding facingportions of the guide system of the functional accessory module forlifting thereof, according to one or more embodiments. FIG. 10F is anelevation view taken from the same perspective as FIGS. 10B and 10E, butafter actuation, in a second direction, of respective rotary elements ofthe first drive system of the vehicle with corresponding facing portions926 of the guide system of the functional accessory module for settingthe functional accessory module upon an underlying support surface and,as shown, thereafter elevating the vehicle 712 within the functionalaccessory module 918, according to one or more embodiments.

FIG. 11A is a rear perspective view depicting deployment of a functionalaccessory module, such as the exemplary FAM 918 depicted in FIGS. 10A to10F, with a flow rack structure 1120 dimensioned and arranged to supplyitems such as fast moving commercial goods (not shown) in an inventorymanagement system 1100, according to an illustrative embodiment. It willbe recalled, with reference to FIGS. 10A to 10F, that dynamicallydeployable FAMs as FAM 918 may include one or more docking or retentionclips, as upper and lower docking clips indicated generally at 927 a and927 b, respectively. FIG. 11B is a side elevation of the illustrativeembodiment of FIG. 11B, just prior to docking of the functionalaccessory module 918 with the flow rack structure 1120 in accordancewith one or more embodiments. In this instance, flow rack structure 1120includes a corresponding pair of upper and lower docking clips,indicated generally at 1027 a and 1027 b, with these being dimensionedand arranged to receive and retain a portion of clips 927 a and 927 b.

To bring the respective pairs of upper and lower docking clips intointerlocking alignment, the first and/or second drive system(s) ofvehicle 712 is/are operated to move FAM 918 in the direction of thehorizontal arrow. When the two structures are as close to one another asdepicted in FIG. 11A, gear wheels of vehicle 712 are driven in thedirection opposite to the direction required to lift the FAM 918, duringwhich the FAM 918 moves in the direction of the vertical arrow. Thisrotation is continued until surfaces of FAM 918 are supported by theunderlying support surface. The resulting interlock betweencomplementary pairs of docking clips secures FAM 918 against flow rackstructure 720 in the position shown in FIG. 11A. It should be borne inmind that other mechanisms may be employed to defeasibly interlock FAM918 and rack structure 1120, without departing from the spirit and scopeof the present disclosure.

In some embodiments, and as noted previously, structures performed thefunctions of FAMs 918 may be integrally formed as part of the rackstructures 1120 or attached to the rack structured 1120 using fasteners,clamps, and the like such that coupling/decoupling and separation is notperformed by coordinated movements of the vehicle 712. It suffices tosay that any such rack structure need only define task activity zonesinto which the vehicles, as vehicle 712, can enter, climb, align with astorage surface, and perform an item exchange between a surface of therack structure and the transfer platform of the vehicles.

In any event, and turning now to FIG. 11C, there is shown a sideelevation of the illustrative embodiment of FIGS. 11A and 11B,subsequent to docking of the FAM 918 with the flow rack structure 1120and elevation of the vehicle 712 within the task activity zone Z. Asdepicted, the illustrative rack structure includes three tiers ofstorage locations, indicated generally 1102, 1104 or 1106, respectively.The vehicle 712 is shown as having reached a vertical elevation withintask activity zone Z of FAM 918 that is aligned with the uppermoststorage tier 1106, and the rollers 711 of the vehicle transfer mechanismhave already been activated to advance container C onto a target surfaceof rack structure 1120.

In some embodiments consistent with the present disclosure, the clutchmechanism utilized in, for example, the vehicle 200 depicted in FIGS. 2Ato 2I, may be omitted. In one such embodiment, a first onboard motor isused to independently rotate one of the central drive elements, as driveelement 752 b, while a second onboard motor is used to independentlyrotate the other of the central drive elements. Turning in eitherdirection, in such an embodiment, is achieved by rotating the centraldrive elements in opposite directions or, for a larger turn radius, bothin the same direction but one faster than the other. In addition, theomnidirectional wheels on one side, as wheels 754 b and 756 b may bedriven by the same onboard motor(s) being used to drive the centraldrive element on that side. By way of further example, a single, thirdonboard motor may be used to drive all of the omnidirectional wheels, asdescribed previously in connection with vehicle 200. In any of theforegoing example, and others, the transfer mechanism may be driven byyet another onboard motor, obviating the need for a clutch mechanism.

In one or more other embodiments of inventory management system 1100,vehicle 712 incorporates the clutch mechanism-equipped second drivesystem (FIGS. 3A to 4C) and transfer mechanism (FIGS. 2D to 2I) featuresof vehicle 200. In such embodiments, an onboard motor (not shown) ofvehicle 712 is operated to cause vehicle 712 to climb within activityzone Z. In the present instance, gear wheels of vehicle 712 rotateagainst teeth of track 926. As a result, forward omnidirectional wheels,as wheel 754 b, and rear omnidirectional wheels, as wheel 756 b, leavetheir respective positions of support upon the underlying supportsurface. In addition, pivotable carriers (not shown) drop the seconddrive elements, of which only second drive element 752 b is shown and,at the same time, one or more clutch mechanism(s) (not shown) areengaged. Engagement of the clutch mechanism(s), in turn, enablesrotation of the sprockets 717 b. Rotation of one or more additionalmotors drives endless carrier 714 b and cause the transfer mechanism toadvance the container C onto surface 1106 of the storage structure 1120.

With continuing reference to FIG. 11C, it should be noted that if thepitch angle of the storage tiers is sufficient, it may be possible forcontainers C to advance solely by action of gravity in for example, apassive roller or a chute configuration. In the embodiments exemplifiedby FIGS. 11D to 11G, however, the multi-level rack structure (s 1120 ofinventory management system 1100 includes a discharge assistant at eachlevel. In some embodiments, and as already described in connection withFIG. 9 , the discharge assistant comprises a plurality of parallel belts1128 and, optionally, sensors for determining the timing for advancinginventory items deposited by vehicles, as vehicle 712, toward the endclosest the picker(s).

FIG. 11D is a front perspective view of the illustrative embodiment ofFIGS. 11A to 11C, depicting elevation of the vehicle 712 within afunctional accessory module 918 into the position shown in FIG. 11C,according to one or more embodiments. FIG. 11E is a top plan view of aninventory management system 1100 consistent with the embodiment of FIGS.11A to 11D, depicting elevation of the vehicle 712 within the taskactivity zone of functional accessory module 918. FIG. 11F is anenlarged, partial top plan view of the illustrative embodiment of FIGS.11A to 11E, subsequent to transfer of container C1 from the transportplatform of the elevated vehicle 712 to target surface 1106 f of therack structure 1120, according to one or more embodiments.

By way of illustrative example, inventory management system 1100 isdeployed in an order fulfillment facility according to an e-commerceapplication. Vehicle 712 supplies containers, as containers C1 and C2which may contain a plurality of individual inventory items. In thisinstance, a warehouse management system (WMS) of the facility hasdetermined that subsets of inventory items, indicated generally atI_(S1), I_(S2), I_(S3), I_(S4), I_(S5), and I_(S6), will be needed atsufficient volumes during the current or an approaching inventorymanagement interval as to justify their continued placement in rackstructure 1120. In embodiments, dynamic placement of inventory itemsutilizing vehicles and FAMs as FAM 918 reduces the time needed toretrieve items so that they can be packaged for shipment as part of ane-commerce operation. By way of illustrative example, a human operatormoves between a packing station and the item transfer area A proximaterack structure 1120, which isolates them from vehicle 712 operating initem transfer area B.

With reference to FIGS. 11E and 11F, it will be seem that vehicle 712has discontinued its ascent within the task management zone of the FAM918 a, having stopped at the transfer position associated with aplurality of third tier locations indicated generally at 1106 a to 1106g which are also collectively identified at numeral 1106 in FIGS. 11Cand 11D.

At least some subsets of the items, as subsets I_(S1) to I_(S5), as wellas the contents of the container C1 and those containers in storage area1100 g continue to be needed at sufficient volumes—during a current oran approaching inventory management interval—as compared to other itemsprocessed by the facility, to flow rack structure 1120. In thisinstance, the WMS has determined that other items stored in rackstructure 1120—such as those items stored at location 1106 f incontainer C2 for retrieval during an earlier phase of the currentinventory management interval (and/or during a preceding one)—no longerhave sufficient priority as to be present in the same quantity, or atall, in rack structure 1120. In embodiments consistent with the presentdisclosure, the same vehicle 712 and FAM 918 a, or a differentvehicle-FAM pair, may be used to replace container C2 with a differentcontainer. An exemplary sequence of such a replacement operation will bedescribed by reference to FIGS. 11G to 11I.

FIG. 11G is a top plan view depicting of the illustrative embodiment ofFIGS. 11A to 11F, depicting temporary deployment of FAM 918 a into aposition of interlocked alignment with storage location 1106 f of rackstructure 1120. While in this position, the vehicle 712 a is elevatedwithin task activity zone of FAM 918 a to retrieve container C2 in amanner as previously described, and then the vehicle 712 a returns tothe underlying surface. Further operation of the gear wheels causeslifting of FAM 918 a from the underlying support surface, and thevehicle 712 a relocates the FAM 918 a to the solid line position shownin FIG. 11G. In the illustrative embodiment of FIG. G, movements of thevehicle 712 a, as well as those of vehicles 712 b to 712 d shown in FIG.11G, are guided by a grid of fiducial markings, indicated at 1132, whichare sensed by one or more imaging sensors (e.g., cameras) of eachvehicle (not shown). It should, however, be understood that otherposition tracking systems and techniques may be utilized withoutdeparting from the spirit and scope of the present disclosure.

In one or more embodiments, vehicles 712 utilize capacitors which mustbe periodically charged. In some embodiments, the vehicles return to acharging station remote from rack structure 1120 while in others,electrical charging ports (not shown) are present in situ, proximate thetrack structure such that the vehicle 712 a need not exit the taskactivity zone of FAM 918 a. FIGS. 11H and 11I are rear elevation viewsof the rack structure 1120 of inventory management system 1100,subsequent to the transfer of item C2 from vehicle 712 a to vehicle 712b described above. In this instance, vehicles 712 a and 712 b have eachreturned to a charging station for restoration of power prior toassignment of further inventory management task(s). As such, FIG. 11Hdepicts vehicle 712 c as having entered FAM 918 a, while FIG. 11Idepicts vehicle 712 c has having elevated item C3 within the taskmanagement zone of FAM 918 a whereupon a transfer of item C3 to storagearea 1106 e (FIG. 11G) is completed by operation of the transfermechanism of vehicle 712 c.

FIG. 12 is a partial perspective view depicting a part of an inventorymanagement system 1200, which may form part of the system shown in FIG.1C and utilizes autonomous vehicles 1212 to transfer containers 1202 ofinventory items back and forth between a picking area and a verticalarray of storage locations indicated generally at 1220, according to oneor more embodiments. In this instance, material handling systemincorporates all of the elements of the system 900 shown in FIG. 9 , butfurther utilizes vehicles 1212 and the array of storage locations 1120as elements of an automated storage and retrieval system (AS/RS). Sothat dynamically deployable FAM structures 718 a and 718 b may beutilized alongside the structure which defines the vertical array ofstorage locations 1220, the vehicles 1212 may be configured in the samemanner as the previously vehicles 200 and 712. However, it should beborne in mind that where such compatibility is not required, as forexample, would be the case for embodiments which rely on flow rackstructures 1120 and storage locations 1220, then those features of thevehicles which are directed to maintaining maneuverability under heavyload need not be incorporated.

In any event, and turning now to FIGS. 13A to 13E, an process forstorage and retrieval of items within an array of storage locations aslocations 1220 of FIG. 12 will now be described in detail. Turning firstto FIG. 13A, there is shown a front elevation view depicting a pluralityof automated guided vehicles 1212 a to 1212 e being operated within orabout a rack structure 1300. As in previously described embodiments, thevehicles perform various item replenishment and/or item retrieval tasksand in this instance, some of those tasks involve retrieving containersfrom or returning the containers (or totes) to storage locations 1315 a,1315 b, 1315 c and 1315 d.

As seen FIGS. 13A and 13B, Vehicles 1212 b and 1212 d are depicted asbeing supported by an underlying support surface as they maneuver withinareas Z1 and Z2 directly below the storage locations. In embodiments,areas Z1 and Z2 are maneuvering zones which permit the vehicles toconveniently move into or out of the rack structure 1300. For example,in FIG. 13A, vehicle 1212 a is seen entering the structure 1300 andpassing under the support surfaces 1322 of a first vertical array ofstorage locations. The support surfaces 1320 and 1322, in this instance,are defined by shelving channels which are supported by a plurality ofvertical support columns of which support columns 1304 a, 1306 a, 1308 aand 1310 a are depicted in FIG. 13A. The vehicle 1212 b is shown havingexecuted a 90 to 270 degree turn in order to continue traveling upon thesubstantially horizontal support surface underlying the maneuvering zoneZ1. Vehicle 1212 c, on the other hand, has entered the column withinwhich it will ascend. In embodiments, vehicle 1212 c ascends in the samemanner as vehicle 1212 e, which is shown as having already ascendedwithin a drive column behind the drive column occupied by vehicle 1212c. More particularly, each of vehicles 1212 a and 1212 e move withintheir respective drive column by actuation of a drive system which, asin previous embodiments, may include gear wheels having teeth forengaging complementary teeth defined by inwardly facing track segmentsformed along the four support columns. Vehicle 1212 d is shown travelingalong the support surface underlying zone Z2 having, for example,entered zone Z2 from a location external to structure 1300 or being nowready to exit.

FIG. 13B is a side elevation view depicting the rack structure 1300populated within a number of containers or totes, including totes T_(a),T_(b), T_(c) and T_(d). a plurality of vehicles operating to performvarious item replenishment and/or item retrieval tasks as, for example,part of the inventory management system 1200 of FIG. 12 , according toone or more embodiments. Here again, tote 1212 a is shown having enteredthe leftward most drive column, indicated at D1, via maneuvering zoneZ1. In this regard, and with reference now to FIG. 13C, it will be seenthat the structure 1300 may incorporate an array of parallel guiderails, as rails R1 and R2, which define a gap g_(G) between them. Thegap is dimensioned and arranged to receive corresponding alignmentstructures on the vehicles so as to enable entry, exit and reorientationof the vehicles without damage to each other and the rack structure.Such structures have already been described in connection with thevehicle 200 and such details are omitted herein in the interest ofclarity and ease of description. It suffices to say that to the extentsuch structures are present on the vehicle, additional alignmentstructures incorporating one or more gaps may be included to guide thevehicles. For example, as seen in FIG. 13C, a second floor mountedalignment system 1350 incorporates a circular shaped, plate-like memberhaving an intersecting pattern of gaps. In this instance, vehicle 1212 bcan be seen using alignment system 1250 to reorient itself angularly as,for example, in preparation of a right turn for travel within zone Z2.

As yet another exemplary alignment structure, embodiments consistentwith the present disclosure may include a third floor mounted alignmentsystem 1340 which consists of a pair of plate members separated by gapg_(G). In this instance, the gap defined by alignment system 1340 isoriented with those defined by alignment system 1350 so as to permit avehicle to quickly and easily traverse the entire width of thestructure—from zone Z1 to zone Z2, but angular reorientation within thedrive columns D1 to D6 is prevented.

As mentioned above, structure 1300 is dimensioned and arranged such thatthe vehicles may enter and exit from various locations beneath thestorage locations, allowing for flexibility in the installation ofpicking and/or replenishing stations. With particular reference to FIGS.13D and 13E, the rack structure 1300 may employ a network of reducedcross-section support sections, indicated generally at 1370, relative tothe support columns which support the storage locations, as supportcolumns 1304, 1306 a, 1308 a, and 1310 a of FIG. 13A. In someembodiments the reduced cross section supports 1370 are telescopinglyreceived and affixed at a desired location by fasteners, welding or thelike.

In one or more embodiments, retractable guide wheels may be omittedwithout subjecting the vehicles from damage. With particular referenceto FIG. 13E, it will be observed that the guide system 1380 of the rackstructure 1320 includes a specially contoured (relaxed tolerance)transition zone indicated generally at 1380 a. The guide system 1380,inclusive of the transition zone 1380 a, is mounted on opposite sides ofsupport 1370 but not on the other two sides. Within the transition zone,gaps are formed between the teeth of the track, such that the teeth ofthe vehicle gear wheels can freely pass by without damage. This guidesystem arrangement enables the vehicles to drive directly into the drivecolumns without first having to reduce the spacing between guide wheels1320 a and 1320 b, but it also enables the vehicles to move up and downwithin immediately adjacent columns, as best shown in FIG. 13B.

FIG. 14A is a block schematic view depicting the allocation ofFAM-assisted inventory management tasks among a plurality of vehicles,by a controller, indicated generally at reference numeral 1450.Controller 1450 organizes a plurality of automated guided vehicles intorespective groups of one or more vehicles. A first of the groups ofvehicles, indicated at 1402-1 to 1402-n, has no FAM association. As willbe recalled by reference to FIGS. 1A to 1C, FIG. 9 , and FIG. 12 , notall tasks require the use of a FAM. In addition, after having terminateda FAM association, a vehicle may return to a charging station and duringthis time, be ineligible to receive an inventory management taskassignment from controller 1450. A second of the groups of vehicles,indicated generally at 1404-1 to 1404-n, may be associated with FAMsselected from a first category or group of FAMs and a second category orgroup of FAMs. By way of example, FAM category 1 may include anauxiliary adapter as the previously described FAM 714, while a FAMcategory 2 may include the displaceable rack FAMs indicated at 718. Athird of the groups of vehicles, indicated generally at 1406-1 to1406-n, may include the auxiliary FAMs 614 as well as the bintransporting FAMs 618. A fourth of the groups of vehicles, indicated at1408-1 to 1408-2 may include the FAMs 918, used to allocate inventory to(and optionally from) flow rack modules, as depicted in FIG. 9 .Finally, controller 1450 also tracks the locations of any FAMs which arepresently unassigned.

FIG. 14B is a block diagram depicting the subsystems of a plurality ofguided vehicles 1412-1 to 1412-n, according to one or more embodiments.Each vehicle, as vehicle 1412-1 comprises a controller comprising aCentral Processing Unit (CPU) 103, a memory 105, and communicationinterfaces 1407. In some embodiments, the communication interfacescomprise one or more wireless transceivers compliant with correspondingwireless transmission protocol(s) such as IEEE 802.11, with theinterfaces of a vehicle being used to communicate with other vehicles,as in a peer-to-peer topology, or with a central controller. In thelatter regard, vehicles 1412-1 to 1412-n may include position sensors,indicated at 1413, and object sensors 1415 and use the interfaces tocommunicate sensed information with a master controller, as controller1450 of FIG. 14A. The position sensors, in one or more embodiments,include onboard imaging sensors for determining when the vehicle haspassed over a fiducial marking positioned on an underlying supportsurface. Alternatively, however, the vehicles 1412-1 to 1412-n mayutilize signal triangulation and/or any other conventional technique fordetermining their respective locations relative to one another orenabling the controller to do so.

With continued reference to FIG. 14B, it will be seen that each AGV, asAGV 1412-1 includes a power supply 1417 which may, for example, be arechargeable power supply comprising ultracapacitors, one or morebatteries, or a combination of these. In one or more embodiments, thepower supply drives a first motor 1419 of first drive system 1409. Firstdrive system 1409 may further include gear wheels driven by the firstmotor and used, for example, to drive the vehicle vertically within aFAM as FAM 918, or within the AS/RS rack structure 1320. In the presentinstance, the power supply 1417 also supplies power to a second drivesystem 1411, which includes a second motor 1421 and, optionally, a thirdmotor 1423.

The CPU 1403 may comprise one or more commercially availablemicroprocessors or microcontrollers that facilitate data processing andstorage. Various support circuits facilitate the operation of the CPU1403 and include one or more clock circuits, power supplies, cache,input/output circuits, and the like. The memory 1405 comprises at leastone of Read Only Memory (ROM), Random Access Memory (RAM), disk drivestorage, optical storage, removable storage and/or the like.

FIG. 14C is a block schematic diagram of a controller 1450 which may beresponsive to instructions received from a warehouse automation system(WMS) 1440 to coordinate the assignment and performance of inventorymanagement task activities by a plurality of vehicles and FAMs, such asthose assigned to AGV task groups 1402-1, 1404-1, 1406-1 and 1408-1. Thecontroller 1450 comprises a Central Processing Unit (CPU) 1451, supportcircuits 1455, a memory 1452, user interface components 1454 (which mayinclude, for example, a display with touch sensitive screen or aseparate keyboard), and communication interfaces 1453. In someembodiments server 1450 comprise one or more wireless transceiverscompliant with corresponding wireless transmission protocol(s) such asIEEE 802.11.

The CPU 1451 may comprise one or more commercially availablemicroprocessors or microcontrollers that facilitate data processing andstorage. The various support circuits 1455 facilitate the operation ofthe CPU 1451 and include one or more clock circuits, power supplies,cache, input/output circuits, and the like. The memory 1452 comprises atleast one of Read Only Memory (ROM), Random Access Memory (RAM), diskdrive storage, optical storage, removable storage and/or the like. Insome embodiments, the memory 1452 comprises an operating system 1456 andone or more inventory management applications. In some embodiments, theinventory management applications include a task agent manager module1460, an AGV traffic management module 1470, a state/event monitoringmodule 1480, and a data repository 1490.

In one or more embodiments, the task agent manager 1460 is configuredwith an inventory management task processor 1461, a dynamic inventoryslotting analyzer 1462, a subtask sequence identifier 1463, a taskpriority manager 1464, an event notification detector 1465, a statetransition detector 1466, an AGV selector 1467, and a FAM selector 1468.The inventory management task processor 1461, through execution ofinstructions by CPU 1451, processes inventory management task requestsreceived from the WMS 14440. A list of the subtasks associated withreceived task requests includes, for example, those subtasks listed inthe following table:

Sub Task Description 1 Relocate AGV to Charging Area 2 Relocate AGV tospecified location (of FAM 1) 3 Dock AGV with FAM 1 4 Relocate AGV + FAM1 to specified location (of FAM 2) 5 Dock AGV/FAM 1 with FAM 2 6Relocate AGV + FAM 1/FAM 2 to specified location 7 Decouple FAM 2 atspecified location 8 Relocate AGV + FAM 1 to specified location (of FAM3) 9 Dock AGV/FAM 1 with FAM 3 10 Relocate AGV + FAM 1/FAM 3 tospecified location 11 Decouple AGV from FAM 1/FAM 3 at specifiedlocation 12 Relocate AGV to specified location (of FAM 4) 13 Dock AGVwith FAM 4 14 Relocate AGV + FAM 4 to specified location 15 Relocate AGVto specified location (of storage area) 16 Operate transfer mechanism ofAGV at specified location (for retrieval) 17 Relocate AGV to storagearea (for replenishment) 18 Relocate AGV from storage area todestination (for transfer)

Dynamic inventory slotting analyzer 1462, in one or more embodiments,allocates inventory items among different storage areas, based onavailable manpower resources, distance between where those resources arestationed, and respective pools of storage locations, and the known orforecast demand for items over the current and at least one subsequentinventory management interval (e.g., 60 to 120 minutes). Subtasksequence identifier allocates the subtasks comprising each inventorymanagement task among one or more vehicles and FAMs. By way of example,a first AGV may lack sufficient power resources to complete all subtaskelements of an entire task. In such event, the first AGV may be directedby the controller to transition an inventory item and/or FAM to a secondAGV, with the timing being sufficient to enable the first AGV to returnto a charging station and recharge, before returning to the pool oftask-eligible AGVs. To facilitate such functionality, task agent manager1460 further includes an event notification detector 1465 to determinewhen a critical power level threshold has been crossed as well as astate transition notification detector 1466 to determine when other AGVand FAM assets have returned to task-eligibility status.

The AGV and FAM selectors, 1467 and 1468, respectively, utilizeavailable position, power and remaining subtask data to select anappropriate utilization of AGV and FAM resources to complete anysubtasks which would otherwise remain unfinished by another AGV, andwhere possible, to ensure tasks are assigned to those AGVs and FAMswhich have the resources to complete them. The AGV and FAM selectors mayrely upon information received from the position analyzer 1475 andpriority monitor 1476.

In some embodiments, traffic management of the AGVs is performed bytraffic management module 1470 of controller 1450. In such cases,position, speed and direction data is collected from the vehicles atregular intervals by the controller. The position data is analyzed, andpath segment selector 1474 selects paths for each vehicle over the nextcontrol interval to ensure that there are no collisions with othervehicles, with personnel, or with fixed structures. The updatedinstructions corresponding to the path selections, inclusive of headingand direction, are transmitted by the controller back to the vehicles.In other embodiments, however, the vehicles do not rely on thecontroller for relative positioning instructions, but rather solely fordestination and task assignments, with the vehicles instead relying oninternal data gathering and spatial analysis capabilities.

To facilitate the aforementioned operations, the controller 1450 of FIG.14C includes a data repository which reflects an up to date location ofall inventory items for which management and allocation responsibilityhas been assigned by the WMS, as well as a map of the FAM locationswithin the facility. In addition, to facilitate the scheduling ofpreventive maintenance procedures, usage statistics are collected forall AGVs and FAMs having moving parts, so that at regular intervals,parts can be inspected, lubricated, and/or replaced.

From the above description, it will thus be appreciated that in someembodiments, a first type of rack structure within which vehicles areconfigured to operate according to the first mode of operation defines aplurality of vertical arrays of storage locations separated by aisles ofcolumns within which the vehicles climb. Such rack structures areexemplified by the embodiment of FIGS. 13A to 13E wherein the guidesystem comprises parallel tracks dimensioned and arranged such thatvehicles can enter a climbing column not from an end of thecorresponding aisle within which the column is disposed but, rather,from the side of the column. That is, the vehicles are configured tomove upon a support surface portion which is directly below the storagelocations of the array, such that they may enter any climbing columnfrom a direction transverse to the longitudinal axis of the aisle ofclimbing columns. Thus, more than two vehicles can enter and/or leaverespective climbing columns of the same aisle at the same time.

In some embodiments, the depth of the space allocated to the storagelocations and, consequently, to the paths along underlying supportsurface upon which the vehicles travel to enter and exit a climbingcolumn, are of sufficient length to enable two vehicles to turn andtravel along paths parallel to one another (whether in the same or inopposite directions).

In some embodiments, a second type of rack structure within which thevehicles are configured to operate according the first mode of operationdefines a plurality of feed flow surfaces which are served by an aisleof climbing columns along which parallel tracks of a guide system arevertically arranged. Such embodiments are exemplified by FIGS. 11A-11H.In one such embodiment, the feed flow surfaces are defined by aplurality of non-driven rollers which are dimensioned and arranged tofeed inventory items unidirectionally by gravity, as they are receivedfrom a vehicle within one of the climbing columns. Additionally, oralternatively, at least some of the feed flow surfaces are defined by aplurality of driven rollers configured to advance the items in a firstdirection, away from a vehicle within one of the climbing columns as forretrieval by one or more fulfillment station operators and to advancethe items in a second direction opposite the first, as for transfer ofan item to a vehicle in a climbing column during a replenishmentoperation. In an alternate example, the feed flow surfaces may bedefined by a plurality of horizontally oriented belts driven in thefirst and second directions to serve the same retrieval andreplenishment functions as the drive rollers described previously.Although the climbing columns in the case of FIGS. 11A to 11H aredepicted as being vertically and horizontally displaceable by thevehicles according to the second mode of operation, in other embodimentsconsistent with the present disclosure, these are stationary.

FIG. 15 is a flow chart depicting a process 1500 by which inventorymanagement tasks may be assigned to one or more vehicles and FAMs. Theprocess 1500 is entered at 1502 and proceeds to 1504 where an inventorymanagement task request is received. The process 1500 proceeds to 1506where the process identifies the sequence of subtasks which areapplicable to the task requested at 1504. From 1506, the process 1500proceeds to 1508, where the process determines which AGV and FAMresources are needed to complete one or more of the subtasks identifiedat 1506. From 1508, the process 1500 proceeds to 1510, where the processdetermines the time and power requirements for completion of the one ormore subtasks identified at 1508. The process 1500 proceeds to decisionblock 1512.

At decision block 1512, the process determines whether there are anycurrently pending tasks having a higher priority than the task requestreceived at 1504. If not, the process proceeds to decision block 1514,where the process determines whether the needed AGV and FAM resourcesare available for assignment to the task request specified at 1504. Ifnot, the process returns to decision block 1512, but if so, then theprocess proceeds to 1516 and the process establishes a new taskassociation between the AGV and one or more FAMs. From 1516, the processproceeds to 1518, where the process transmits instructions to the AGV(s)identified at 1514. The process proceeds to decision block 1520. Atdecision block 1520, the process determines whether or not all assignedsubtasks have been completed. If not, the process returns to 1508 forallocation of additional resources. If so, the process proceeds to 1522and determines whether the inventory management cycle is still activeand open, if so, the process returns to 1504. If not, the processproceeds to 1524 and terminates.

In the event the process 1500 determines at 1512 that higher prioritytasks are pending, then the process proceeds to 1526 and assigns apriority to the task request received at 1504 and the process proceedsto 1528. At 1528, the process assigns the current task sequence to atask queue. In this regard, it should be noted that there may be manysuch task queues. Of the tasks remaining in the assigned task queue, theprocess determines which has the current highest priority and theprocess returns to decision block 1512.

FIG. 16 is a flow chart depicting a process 1600 by which inventoryitems are dynamically allocated among various storage areas over aseries of consecutive inventory management intervals, according to oneor more embodiments consistent with the present disclosure. The process1600 is entered at start block 1602 and proceeds to 1604, where adynamic slotting interval counter is initialized. In some embodiments, afacility may be operate over two 8 hour shifts or 16 hours. In thisinstance, slotting intervals of one hour are used such that the processadvances to 1606 and increments by 1 to signify each slotting interval.At 1606, received inventory management tasks scheduled for completionduring a current or approaching slotting interval are analyzed, and adetermination is made as to which inventory items should be placed infirst storage areas reserved for faster moving goods and which may berelocated to second storage areas appropriate for slower moving goods.The process assigns inventory items of a first subset to the firststorage areas and inventory items of a second subset to the secondstorage areas. The process proceeds to 1608.

At 1608, the process 1600 initiates operation of a first group of AGVsto begin relocating a first subset of inventory items from the secondstorage areas to the first storage areas, and at 1610, initiatesoperation of a second group of AGVs to begin relocating a second subsetof inventory from the first storage areas to the second storage areas.The process proceeds from 1610 to 1612. At 1612, the process operates aplurality of AGVs to transfer at least some inventory items from atleast a first of the relocated first subsets of inventory items, to adestination area. From 1612, the process proceeds to 1614 where theprocess operates a plurality of FAMs and AGVs to transfer inventoryitems from at least the first of the relocated subsets of inventoryitems, to a destination area. The process proceeds to 1616.

At 1616, the process increments the dynamic slotting interval counter byone and proceeds to 1618 for determination of whether there are anyremaining increment cycles remaining in the current inventory managementcycle. If so, the process returns to 1606 and performs analysis for asubsequent slotting window. If not, the process proceeds from decisionblock 1618 to termination block 1620, and ends.

FIG. 17 is a flow chart depicting a process 1700 according to one ormore embodiments consistent with the present disclosure. A controller ofan automated guided vehicle executing process 1700 operates the vehicleto perform inventory management tasks using only the onboard resourcesand capabilities of the vehicle, according to a first mode of operationand, according to a second mode operation, using additionally theresources and capabilities of one or more FAMs. The process 1700 isentered at 1702 and proceeds to 1704 where the method 1700 determinesthe mode of operation needed to perform an inventory management task.The process 1700 proceeds to 1708 where the process identifies if thefirst mode of operation applies and, if so, process 1700 proceeds to1710.

At 1710, according to a first mode of vehicle operation, method 1700controls rotation of a first plurality of drive elements of a seconddrive system of the vehicle, and advances to 1712 where method 1700aligns a first plurality of drive elements of a first drive system witha guide system disposed along an array of storage locations of a rackstructure. From 1712, method 1700 advances to 1714 where method 1700controls rotation of the second plurality of drive elements of the firstdrive system to displace the vehicle vertically to reach one of thestorage locations or, alternatively, to depart from one of the storagelocations. Regardless of whether method 1700 is performing a task bywhich an item is being retrieved from a storage location of the rackstructure, rather than to the storage location, method 1700 performs1710 through 1712 two times—the first time first to enter the rackstructure and reach the target storage location for operation of anonboard transfer mechanism of the vehicle to retrieve or deposit theitem and the second time reversing the order to leave the target storagelocation and exit the rack structure.

In some embodiments, method 1700 is performed using vehicles in whichthe first plurality of drive elements of the first drive system aremaintained at a fixed distance from one another and corresponding to aspacing between parallel tracks of a guide system, the execution ofmethod 1700 does not require such a configuration. In alternateembodiments consistent with the present disclosure, for example, thealignment of 1712 may be achieved by performing additional steps ofutilizing an additional drive mechanism to move the first plurality ofdrive elements of the first drive system toward one another beforeentering an opening defined in the rack structure aligned with theparallel tracks and then moving the first plurality of drive elements ofthe first drive system away from one another to bring respectiveengagement surfaces into positions where rotation of first plurality ofdrive elements initiates the vertical displacement of 1714.

In any event, and with continued reference to FIG. 17 , process 1700proceeds from 1714 to decision block 1716, whereupon the process 1700determines whether additional tasks remain and, if so, the processreturns to 1704. Method 1700 is additionally and alternativelyconfigured to proceed from 1708 to 1720, where according to a secondmode of operation, method 1700 controls rotation of the first pluralityof drive elements of the second drive system to cause the vehicle toenter or exit an opening defined by an accessory module. Method 1700proceeds from 1720 to 1722 where the method controls rotation of thefirst plurality of drive elements of the second drive system to displacethe vehicle and accessory module horizontally. Method 1700 proceeds from1722 to 1724 where the method controls rotation of the first pluralityof drive elements of the first drive system to displace the accessorymodule vertically.

It should be borne in mind that the order in which 1720 to 1722 areperformed depends upon the particular task assigned. For example, thetransfer of an accessory module from one location of an inventorymanagement facility to another is accommodated by performing 1724 afirst time, after the vehicle enters the accessory module at the firstlocation, before step 1722 is performed. Once method 1700 performs 1724to lift the vehicle at the first location, step 1722 is performed torelocate the lifted accessory module. 1724 is re-performed to lower theaccessory module onto the underlying support surface at the second ortarget location, and step 1720 is again performed to withdraw thevehicle from the accessory module.

In some embodiments, such as where a first accessory module serves as anadapter to lift a second accessory module, steps 1720 through 1724 areperformed by method 1700 to retrieve and relocate the first accessorymodule to the location of the second accessory module, and then steps1720 and 1724 are re-performed by the vehicle first accessory modulepair entering, lifting, and horizontally displacing the second accessorymodule.

Although the invention has largely been described and illustrated in thecontext of the movement of inventory in a warehouse, a fulfillmentcenter, or a distribution center, the invention should also beunderstood as being directed to the transport of other types of articlesand for various purposes including the aggregation of parts in amanufacturing operation, or the like. Moreover, the foregoingdescription, for purpose of explanation, has been described withreference to specific embodiments. However, the illustrative discussionsabove are not intended to be exhaustive or to limit the invention to theprecise forms disclosed. Many modifications and variations are possiblein view of the above teachings. The embodiments were chosen anddescribed in order to best explain the principles of the presentdisclosure and its practical applications, to thereby enable othersskilled in the art to best utilize the invention and various embodimentswith various modifications as may be suited to the particular usecontemplated.

The order of methods described herein may be changed, and variouselements may be added, reordered, combined, omitted, modified, etc. Allexamples described herein are presented in a non-limiting manner.Various modifications and changes may be made as would be obvious to aperson skilled in the art having benefit of this disclosure.Realizations in accordance with embodiments have been described in thecontext of particular embodiments. These embodiments are meant to beillustrative and not limiting. Many variations, modifications,additions, and improvements are possible. Accordingly, plural instancesmay be provided for components described herein as a single instance.Boundaries between various components, operations and data stores aresomewhat arbitrary, and particular operations are illustrated in thecontext of specific illustrative configurations. Other allocations offunctionality are envisioned and may fall within the scope of claimsthat follow. Finally, structures and functionality presented as discretecomponents in the example configurations may be implemented as acombined structure or component. These and other variations,modifications, additions, and improvements may fall within the scope ofembodiments as defined in the claims that follow.

Accordingly, while the foregoing is directed to embodiments of thepresent invention, other and further embodiments of the invention may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

1. A method of operating an automated vehicle in an inventory managementsystem having a rack structure defining a plurality of destination areasand a guide system, the method comprising: operating a first motor tocontrol rotation of a first plurality of drive elements of the automatedvehicle to move the automated vehicle upon an underlying support surfaceand into a pre-climb position wherein a second plurality of driveelements of the automated vehicle are aligned with and engage the guidesystem; operating a second motor to control rotation of the secondplurality of drive elements to advance the automated vehicle verticallyalong the guide system and into an elevated position of alignment with afirst destination area of the plurality of destination areas; andengaging a clutch mechanism of the automated vehicle while operating thefirst motor to transmit power from the first motor to a transfermechanism of the automated vehicle and thereby transfer a container ofinventory items from the first destination area onto a support surfaceof the automated vehicle.
 2. The method of claim 1, wherein the clutchmechanism of the automated vehicle is engaged by operating the secondmotor to cause climbing of the automated vehicle until the firstplurality of drive elements no longer contact the underlying supportsurface.
 3. The method of claim 2, further including operating thesecond motor to reverse a direction of rotation of the second pluralityof drive elements to thereby cause descent of the automated vehicle intothe pre-climb position and disengagement of the clutch mechanism,whereby operation of the first motor no longer transmits power to thetransfer mechanism.
 4. The method of claim 3, further includingoperating the first motor to control rotation of the first plurality ofdrive elements and move the automated vehicle upon the underlyingsupport surface and away from the pre-climb position.
 5. The method ofclaim 4, wherein the first plurality of drive elements includes a firstpair of omnidirectional wheels, a second pair of omnidirectional wheels,and a third pair of wheels, the method further comprising driving afirst wheel of the third pair of wheels with a first motor and a secondwheel of the third pair of wheels with a third motor.
 6. The method ofclaim 5, further including steering the automated vehicle comprisingoperating the first motor to rotate the first wheel of the third pair ofwheels in a first direction of rotation and operating the second motorto rotate the second wheel of the third pair of wheels in a seconddirection of rotation opposite to the first direction of rotation. 7.The method of claim 6, further including selectively operating first andsecond actuators to exert a respective normal force upon each wheel ofthe third pair of wheels to thereby enhance frictional contact andsteering of the automated vehicle.
 8. A method of operating an automatedvehicle in an inventory management system having a rack structuredefining a plurality of destination areas and a guide system, the methodcomprising: operating a first motor to control rotation of a firstplurality of drive elements of the automated vehicle to move theautomated vehicle upon an underlying support surface and into apre-climb position wherein a second plurality of drive elements of theautomated vehicle are aligned with and engage the guide system;operating a second motor to control rotation of the second plurality ofdrive elements to advance the automated vehicle vertically along theguide system and into an elevated position of alignment with a firstdestination area of the plurality of destination areas; and engaging aclutch mechanism of the automated vehicle while operating the firstmotor to transmit power from the first motor to a transfer mechanism ofthe automated vehicle and thereby transfer a container of inventoryitems from a support surface of the automated vehicle into the firstdestination area.
 9. The method of claim 8, wherein the clutch mechanismof the automated vehicle is engaged by operating the second motor tocause climbing of the automated vehicle along the guide system until thefirst plurality of drive elements no longer contact the underlyingsupport surface.
 10. The method of claim 9, further including operatingthe second motor to reverse a direction of rotation of the secondplurality of drive elements to thereby cause descent of the automatedvehicle into the pre-climb position and disengagement of the clutchmechanism, whereby operation of the first motor no longer transmitspower to the transfer mechanism.
 11. The method of claim 10, furtherincluding operating the first motor to control rotation of the firstplurality of drive elements and move the automated vehicle upon theunderlying support surface and away from the pre-climb position.
 12. Themethod of claim 8, wherein the first plurality of drive elementsincludes a first pair of omnidirectional wheels, a second pair ofomnidirectional wheels, and a third pair of wheels, the method furthercomprising driving a first wheel of the third pair of wheels with afirst motor and a second wheel of the third pair of wheels with a thirdmotor.
 13. The method of claim 12, further including steering theautomated vehicle comprising operating the first motor to rotate thefirst wheel of the third pair of wheels in a first direction of rotationand operating the second motor to rotate the second wheel of the thirdpair of wheels in a second direction of rotation opposite to the firstdirection of rotation.
 14. The method of claim 13, further includingselectively operating first and second actuators to exert a respectivenormal force upon each wheel of the third pair of wheels to therebyenhance frictional contact and steering of the automated vehicle.